How can I get my layer cake to cook more evenly/not burned? I usually make a two layer cake, and I have a family favourite cake recipe which is fool-proof. I now want to start making one layer (thicker) cakes and i am using catering grade tins. I just finished baking my first one.

Because this cake was thicker, I lowered the temp from 180° C, to 170° C. The cake rose well, but the center was liquid till the very end; it also burned on top and I had to leave the cake in for much longer than I usually do (45 minutes instead of 35).

The length of time I baked it for isn't a problem, the cake rose very well too, but what should I change to stop the cake from burning at the top?
In a conventional oven, the majority of the heat is at the top.

You don't mention lowering the oven rack to compensate for the change in height. I'm fairly certain that would solve your problem.

Center rack is normally recommended - if you used a higher rack then that's definitely the reason it burned. But even if you used the center rack, you might need to lower it for a particularly tall cake. You might also need to extend the cooking time slightly to compensate for the lower effective temperature.

Note that this doesn't apply to convection ovens, which have a relatively constant temperature throughout.