I do not know how, but the fuel filler catch has broken on my 2008 TDV8. the First question is where to source a new part and the second is how easy is it to replace. The vehicle is due for a service soon, so is it worth the hassel fixing this myself.

Is it the bit on the actual flap?

See the post below that might help

http://www.rrsport.co.uk/forum/topic22957.html?highlight=

I think the best place is the dealer. If it is the same as mine very cheap and simple to fix  2011 Autobiography Santorini Black

Its the part in the body, both tiny clips have broken off. The rubber and spring mechanism has popped out as well. Silly little part, it still locks on the central locking but swings open otherwise.