@cptblue 

Hey

Any of the AC2 range of extenders should be compatable with the ones you have, the 8630 for example.

Sadly these usually come in packs of 2, I would check ebay as sometimes people like yourself will sell the item single if they only need 1 plug.

@Philbert 

brilliant, thanks Philbert. I'll have a look, probably stick the 2nd one upstairs to boost it there. 
 

many thanks for your help

@cptblue 

You are very welcome