Hi Lee,
Welcome to the addictive world of X10. My main advice would be to shop around, there are plenty of companies selling X10 equipment in the UK.
The best way to locate UK companies selling X10 equipment is via a search engine such as http://www.google.co.uk/. Following are some google.co.uk links that return many of the well known X10 companies in the UK: http://www.google.co.uk/search?q=x10...UK%7CcountryGB also be aware that many alarm companies sell X10 equipment so also try simply searching UK pages for terms such as "alarm company" + "alarm company x10":
http://www.google.co.uk/search?q=ala...UK%7CcountryGB
http://www.google.co.uk/search?q=ala...UK%7CcountryGB
I personally haven't bothered to even look at going down the second hand route but there are also people out there selling X10 modules second hand:
http://www.google.co.uk/search?hl=en...ay.co.uk&meta=
http://groups.google.co.uk/groups?hl...22+module+sell
Note: As with any second hand electrical equipment be very very careful of safety. If in doubt ask a qualified electrician to check the item over. In relation to ebay I would also be very careful of the many scams operating where people *suddenly* ask you to send the money in advance etc....
Hope this helps.
Regards Richard