I made a few changes to the ingredients - for some reason, the only small tub of toffee yoghurt I could find was low fat - but this didn't seem to make any difference. After reading some the comments below (always a good source inspiration on the GoodFood website!) I also decided to buy the cheap own brand toffee rather than something more expensive - worked well too! Plus, this meant that I got to use my hammer in the kitchen again, smashing up the toffee - after placing in a bag. I may of got a bit carried away, as most of the toffee disappeared into the cake on baking, but I think I prefer it that way. I decided against putting chopped up pecans on the top, but instead picked out the 'pretty looking ones' and had a line down the middle - well it was until on baking the cake rose and made it wonky.
This was a very yummy cake and highly recommended - I've only got a few slices left - oops!