Upon inspection of MY inlet manifold it is not at all as described in these post extracts, I have added three photos that show mine and there is a separate inlet manifold for each Dellorto carb with three bolts on top (circled, see pic above) and two underneath (one in view circled, see below) which look practically impossible to get at unless the carbs are first removed. So that defeats my objective. In fact now with this in mind and looking at the carb mountings it feels a lot easier "just" to remove the carbs. 

Here's my original post with what I thought after extensive searching, but clearly wrong.

Having read various posts in techtalk (and other sites) it seems there is a common thread that:

This is a great idea and so obvious:

"only got as far as the penetrating oil " 

and I came to this carbs removal method because I don't want to have to do all it takes to remount the carbs to the inlet manifold (2mm gap all round etc) as commented here:

" I would take the carbs/inlet manifold off first as it was easier for me to do it this way and they come off easily"

except the common problem/complaint is (on various owners clubs sites) 

" The single stud under the manifold is a real pig

but can be easily got at once you can see what you are doing."

and solution to this is:

"It is just possible to reach the inlet manifold bolt (centre under Carbs) with a long extension bar (and if you have got one a universal joint) the torque is not that high"

So it strikes me that cables to remove if the carbs are to be lifted off the car are: choke, accelerator and fuel line - easy enough.

My objective is accessibility to the distributor

(to replace the electronic igniter and with that the long rubber grommet that is practically impossible to get at for fitting - and maybe the mechanical advance springs which must be tired (metal fatigue) at 37 years )

and while I am at it to replace any seal type parts (rubber or cork) that must be past their best after 37 years in place.; the benefit of this being to improve the airflow in to the engine to facilitate carburettor tuning for emissions and m.p.g.

note: I also need to replace the front carb accelerator jet diaphragm spring which is missing.

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This pic shows both inlet manifolds and the gap between them (at least if you know what you are looking at!) 

This pic shows the location and access to the front lower nut (circled), no chance of getting much in there except a short open spanner. The two in the centre are even worse, so given only two of the carb nuts are difficult but not as hard as these i may as well lift the carbs off. You can see the distributor below illustrating how difficult it is to get at it with any tools or at all.