ChrisC

For me it’s a once a year task during MOT, but don’t think it’s necessary at that frequency.  I bet 2 -3 years would be fine depending on mileage, assuming your UJ isn’t sealed for life, as some are. 

Spend plenty of time getting your radiator as stress free as possible, especially mounting and hose connections (including the oil lines).  Depending on your options there is only so much you can do, but spending time getting a stress free radiator will save money in the long term.   I know of one 2021 420R that’s had 4 radiator failures, and at £700+ it’s not funny anymore.

Definitely not a Mazda, looks Type 9 to me.  Notice how your gearbox mount is welded to your chassis, whereas the photo of the Mazda box it’s bolted in. This means your chassis is pre changes needed for the Mazda gearbox.

Have you got ventilated front disc.  If you have then you will have Delphi rear pads, these rattle in the new Caterham branded rear caliper, supplied since 2018 (ish).  It didn’t happen with the refurbished Ford originals.  You can tell if this is your problem, the noise will go away under braking.

My 1993 SuperSprint 1700 kit was supplied with 15” Prisoners 

Remember reading Caterham service schedule (in the back of the handbook) recommending 5 years.  But I no longer have the car, so can’t check.

The hex extension wasn't part of my Oct 2015 360 or my Sep 2019 420 kits.

The hex extension was dropped in later builds, so they are not needed.   How central is your dedion tube, measured from the chassis rail?  It should be within a mm.  If it's not central then the spacing of the a frame could be out.

MBE repair ECUs if connected directly.  But they may not touch it after the first repair because the seals would have been broken.   They replaced a coil pack driver in a mates 420R ECU which was just out of Caterham warranty free of charge, but remember him getting a very reasonable initial quote.

I think if there is a damp issue within a garage you have two choices.  I reduce the possibility of the damp I.e. insulate and heat,  or cocoon with a inflatable (various options exist).  The choice will be dependent on the possibilities associated with the garage.  For example my garage it was better to replace the garage doors, to remove the drafts, it was already installed because it's linked to the house, and moving the boiler into the garage gave a small level of heat that keeps the damp away.

I think for now forget the TPS range and just look down the ITBs and ensure full throttle opens the ITBs fully.  
 

There should be a throttle stop under the throttle pedal, which should be adjusted so you don't push to far, and put the ITBs under strain once wide open throttle is achieved.  As for pedal adjustment it's done by bending the pedal as needed, but this is normally done during build.

There is a story to that, but not for a public forum.

No, bias car be rearward with standard brakes before they have bedded in properly.  It's fine if you have an early morning drive to the IVA centre and plenty of time to work the brakes before the test, not so good if your trailering your car to IVA with brand new brakes.  
Having seen a few IVAs there is always assistance needed to achieve a pass especially with emissions. If we are going to stick to designing a Caterham to pass without this type of assistance the changes would be significant. 
This isn't about safety, if it was the inspectors wouldn't allow it, that much is obvious when you observe the process.  The inspectors also aren't stupid, they have seen the same steering wheel hundreds of times, and know it's going to be changed as soon as the test is over.  It's the same with MOT inspections, they won't risk their license. 

Just a point, my 2020 and 2016 Duratecs had a permanent 12v supply as well as the ignition switch 12v supply.  I can't be 100% certain but I think that was also the case for my 2011 Sigma.   So it seems there are some inaccuracies in that diagram. 

The best IVA check list is the PBC job sheet used by Caterham Gatwick in recent years.  It includes some tricks and tips on tyre pressures to assist with bias and new brakes. 

It's also common for cars of that age to be presented as R or S models, and owners could have purchased instruments to make it look like an R or S model.

Have you got a link to the advert?

You only need the V5C to access where the MOT was carried out, the history is available online with only the registration number. 

Been to three IVA tests, Gillingham and two at Norwich.  I would recommend Norwich (if that's still an option).  But all the tests have been very pleasant experiences, including inspectors making a brew before starting the process. 

All the instructions on setup are based on the last map released by Caterham, without that everything is best guess because the TPS is not being used for the mapping strategy.  With the MAP sensor connected it's driving the decisions, but MAP on ITBs don't tend to work very well.   Your best option is to get the last (latest) map installed and setup according to the instructions at the beginning of this thread.  

Fuel hoses, possibly the hoses are getting on 20 years old, and not E10 resistant.  

Very strange, when the clutch is pushed the crank thrust bearing provides the opposing force to the pressure applied by the CRB.  I have never heard of any crank thrust bearing issues in any modern Ford (unlike modern BMWs), so wouldn't know if this "old school" test is even valid, but a way to measure end float is to see if you can pull and push the main crank pulley (engine off obviously). Any physical moment is probably not a good sign.   

Just looking back at photos from the same area on my 2019 (kit) 420R, and these connectors are not present.    At the bottom of this page you can see the absence of connectors in that area https://caterham420detailedbuildblog.co.uk/2020/02/21/tunnel-side-carpet/.   I suspect the 420 is using a different chassis loom, given the ECU is different Duratec to Sigma (post 2017 ish).

Interesting, I only had a partial wiring diagram for my 2019 420r, and it only showed one power socket, on the car it obviously was located under the fuse box.   The wire supplying the socket was long enough to reach the rear.   Near the handbrake (and in the tunnel) the only connections were for the reverse switch, handbrake warning light and and seat belt warning light (not used).  My 2011 academy car had the power socket supply in the boot (actually tied to the loom as it went down the diagonal behind the drivers seat), but no factor 12v socket.

Yes the link in #8

Final points that make me think there is more going on with this car.  Every 2007 car listed on Pistonheads has a cat, the later heater design and different style VIN plate (font and colour)