seems daft to resrict your market by not posting abroad to me, especially as certain parts are rarer in other countries so could fetch a higher price.

what's the difference to you as a seller? you can quote a shipping rate in uk, and one within europe, rest of the world etc. you still package it up just the same, take it to the post office / courier company / have it collected just the same. just because you're too lazy to find out the costs beforehand? wtf? you either want to sell it or you don't, and with overseas shipping that costs more in the first place, it's very easy to add a few quid in there for the 'extra hassle'