Just get a refund bud.
I know to some mrk2 golfs are desirable and very thin on the ground now but the big picture is, its failed and fucked, they source a engine from the scrappy, bung it in makes sure it starts and stops and that's it give it back which could just be the start of more shit, head gasket failure looming water and oil leaks bla bla
Money back and fuck it off if it was me.
This ∆
In my mates case the garage is 5 minutes away so I can imagine the arse you will get traveling 120 miles to see nothing done
Ask then to pay a portion of the money to get it fixed locally, have a price ready on an invoice etc and if that is not suitable reject the car and get your money back
It'd easier for them to pay 50% of the repairs because collecting a car is going to cost plenty fit starters and if they can make you go away for the cost of recovery they may see that as the simplest solution, even though you will think they've fucked you at least it's local