Seat runner adjustment

[Ballast-ic]

The seat adjustment lever has a lug that engages with holes on the side of the runner to lock it in place. However, in the position I want the seat, behind the hole is the bolt that goes through the floor holding the runners in place, and so the lug does not fully engage. It partially sits in the hole, but then a bump or rapid acceleration knocks it out and the seat lurches back to the next notch.

So question is, can the runners themselves slide forward and back (loosen nuts underneath car and shunt them forward a couple of mm), or are there holes in the bottom of the runners that determine their location? I just need to move the runners so the bolt securing them isn't directly behind the hole for the seat adjustment level lug.

Asking question first, as reading up on seats/runners I get lots of "there be dragons" and it seems to be a fiddly, tricky exercise.

[Edzup Ezzer]

I've just checked mine.  The front part of the seat frame fouls the centre tunnel well before the adjuster gets near the bolts securing the seat to the floor.  That suggests there is something fundamentally different between your car and mine as it's not a problem I could encounter on mine.  I'm pretty sure on my car (difficult to see) that the bolt head sits well down in the runner channel and the adjuster would pass over the top, if it could get that far forward, which it can't (IYSWIM)

[Ballast-ic]

Mine is an SV, so has a bit more space for the seat to move forwards. Being a short ar*e I need it all the way forwards to reach the gears!

[Golf Juliet Tango]

Change the bolts for button head ones?