Many people seem to list items saying they won't send overseas.
Is there a sound reason for this if the Payapal money is paid?

I have no idea why people restrict their potential buyers to the UK only, it makes no sense at all. You have to go to the post office to send it anyway, you can charge the buyer for the extra cost of shipping and you get the money before you send the goods.

The only real risk is that the parcel may be more likely to get lost en route meaning that you have to refund the buyer, you can insure the parcel for that as well if you are worried about it.

I guess fears with regards shipping costs…
I find shipping things overseas is often more expensive than an online quote.
It's not like you can get an advance quote up front for every possible bidding destination.

I thought there was quite a bit of scamming going on with mobile phones @ one point, as in they buy it & pay for it then claim for it not ever having arrived – claim back there money through paypal and walk away with your phone too.
I imagine it's down to how reliable your courier is and what cover/insurance they offer, as european postal services are supposed to be quite rubbish (from what I've heard in the past).

I don't do it anymore because even though I put "please contact me for overseas postage before bidding" some yank didn't bother, won a wheel and then refused to pay the £50 courier charge even though it was the cheapest either of us could find. He then deleted his ebay account. Some people are stupid and I'm not going through a load of hand holding again. Within the UK, postage prices are more standard/acceptable and most people understand the system.

When I sold an item to someone in Germany paypal wouldn't release the money until feedback was left by the buyer or 30 days had passed, no idea why?

Main reason is for certain countries you can get an equivalent "recorded delivery" signed for sort of thing but Latvia etc. seems a little more lax on things like that and then you've got no legs to stand on if buyer pulls a fast one and says things aren't delivered, gets his/her money back and you can't even leave bad feedback even though you know its a scam.

Plus it's a different cost for different countries. It's all a bit of a faff and I'm just lazy and stick with UK only.

Still didn't stop some guy from Latvia buying a frame of mine (before I sorted the eBay settings properly), saying he'd pay, then his mate might be in the UK and would pop over to collect it, then could I post it.