Burnt pain au raisin

There are some days when you trip at the last hurdle. This is one of those days.
I made the croissant dough last night (recipe from Richard Bertinet's Crust ) and proved overnight in the fridge.
Then rolled and rested it.
Made creme patissiere (also from Bertinet's book, not Michel Roux's recipe that I've used before. I wanted to try a different one and see the difference. Bertinet's is thicker and less sweet, better for pastries?)
Rolled out and assembled the pain au raisin.
Proved for 2 hours.
Then put into a hot oven (220C). And then they burnt.  15 minutes was way too long. And the recipe states 18 - 20 mins. I must have had the oven too hot. At that temp our oven loses some definition I think - making the difference between 220 and 240 hard to tell. Must be careful with this in future.
Or perhaps something else in the process? Don't know.
They'll still taste ok - but disappointing. Will make more ;) you know, to test.