I thought i would give everyone an update on everything - just over a year after it all went wrong.
In the end people at Autolusso did the repair, in doing so they have made an impression that they do know what they are doing. The engine is still working over a year later, i've had the oil tested few times and there was no indication that there was anything wrong going on there.
I've done 18k miles since and the engine is still working and behaving as it should - which is pretty good considering that it has been remapped to run at nearly 2.5 bars of boost and nearly twice the amount of fuel.
Nothing has gone wrong with the engine (driveshafts are a different story though).
Also, the garage that did the damage originally paid for almost everything (as the engine and gearbox had to be taken out i had clutch and flywheel changed at the same time and quaife fitted) - but i had to take them to small claims court - which i did myself without any help from a solicitor (they did have a solicitor, but ended up paying me + solicitors costs). And it seems like they are not trading anymore.