In a small bowl, soak raisins in rum. Let sit for 20 minutes.
Preheat oven to 450 F.
In a large bowl, mix cake, bread crumbs, lemon zest and juice, heavy whipping cream, golden syrup, and egg yolks.
Drain the rum from the raisins and mix the raisins in with the other ingredients.
Split the pie dough in half and roll out the first half to fit a 9" pie pan.
Press rolled dough into the bottom of the pan.
Place prepared filling into the pie pan.
Roll out top crust, place over filling, and press together with the bottom crust around the edges to seal. I made a fancy braid on mine with a little of the excess dough, but that is not at all required.
Bake 15 minutes.
Reduce heat to 350.
Bake 20 minutes. Check the crust; if the edges are browning too much, cover with foil or a pie guard.
Bake for another 20 minutes or until the whole crust is lightly browned.