Thanks for all the replies and advice.
Prior to starting this thread I did look online for advice. Apparently, it would appear that it is more common than one would imagine, people paying for items that are for "collection only" and then not collecting the item, something that I've not heard of before with eBay. There seems to be a multitude of differing advice online as to what to do.
The buyer has now made contact with me, offering an explanation, and I am currently looking into to see how the item can be best delivered to the buyer.