How would i check it ?

Met Chris_C tonight and hes a lovely chap.

Let me use his coilpack which he was unsure of the health on.

And it had the same problem. He thinks it could be fuel starvation.

HOWEVER.

Whilst on the way home i had like literally nearly no fuel in the tank and it ran perfectly. Pulled solidly through all the gears.
Put fuel in and it started doing it again. Could it be over fuelling ??

where is the pick up for the fuel pump? Could it be moving about due to the larger amount of fuel in the tank? (its probably not the issue, but going on what you have said . . .) otherwise fuel filter/lines ok?

Does it do it when revving at a standstill?

I had a bit of a think on the way home, given how it pops and bangs after it stutters, I'm back to thinking it's missing spark, or, as you say, over fuelling and weak spark, hence the fuel popping in the exhaust. I still think given how shonky your fuel feed looks from the bits we've seen, I would:
*Firstly, remove the max power adjustable regulator for a standard. Speedy's car ran hopelessly when it had one. Just a shame about that crimped and cut hose... I was going to look at my spare Megane head to see whether that still has a rail on it.
*Secondly, have a poke at what is actually in the fuel system setup that you can't see, under the car and in the tank. The fact your fuel lines are drivers side means they have been fiddled with all the way through.
*Thirdly... erm, well, see where you are at that point.

Really good to meet you too, great to see someone else how is keen with spanners and wants to do a proper job. I really do like 90% of that install, it's been done with care. It's just a shame the last 10% hasn't been, but you'll get there!

That meet is monthly... it's an eclectic set of nutters, but there is some interesting shiny turns up.

It doesn't do it on revving stand still. Also it doesn't do it once the wheels start spinning either. So only when there is resistance :/

It's very bizarre. Gonna check the pick up like said and take some pictures. Also intend to change all the fuel lines and have a mess with the aftermarket regulator and see if it makes a difference.

ok so only under load? Sounds more ignition like now. Guh cars are so confusing.

Yer only under load. But it makes no sense when it has little fuel doing it :/ I'm going to change spark plugs tomorrow and then see if that works. Might try messing with the regulator and see if that makes a difference.

What pressure should my fuel pressure regulator be at ?

3 bar