Well went and got the intercooler replaced as it looked kinda fooked, about 2 inches of gunk at the bottom of the IC so leaking from somewhere.
Can;t tell yet if it's sorted my problem yet as the metal connector pipe on the top of the intercooler now has a boost leak.
Toph said the metal connector doesn;t sit correctly and is a bit loose.
So driving the car last night kinda confirmed I had a leak for sure as it was making a wooshing noise when accelerating and the power was a little delayed and mostly kicked in once the whoosh noise stopped

So I now need the metal connector but not sure what the part is and the price, there's another thread asking for the part number if anyone can help me out.
I'm kinda really hating my car right now, I was happy for a bit yesterday when Toph drove my car as it was proper shifting and had alot of poke and picked up really well.
I was really lucky as the new intercooler had a MAP sensor on it aswell so that's brand neqw and the intercooler is also.
Keeping my fingers crossed very tightly now that this sorts my MPG issue otherwise it'll kinda be £210 down the drain, hoping that is not the case.