I rent a house with a Teba too. It's so old that the hob location graphics have worn off the top.
I too found that it burnt the bottom of buns but with the oven being fan assisted I just reduced the temp and made sure I was using silicon sheets and trays as they don't hold the heat like a metal one and therefore the bases of cakes and buns do not burn.
Hope that helps.
Georgina
September 2009