Temperatures in a Fan oven.

Hi, I don't know if this is something you will be able to help with, but here goes.

I have recently had to buy a new electric fan oven, and everything seems to be coming out overcooked, especially my baking. My scones that I've made hundreds of times over the years, are coming out really dry, and I made Delia's Victoria Sponge cake the other day, that is also one of my go to recipes, and that came out so dry that even masses of jam and whipped cream didn't help...

I am guessing that the oven is running too hot, but short of buying one of those fancy electric oven thermometers to see exactly by how much, do you have any ideas how I can overcome my problem?

Cheers, Damian