Firstly - my unit seems to be type AV600 (which didn't appear in the drop-down list) so sorry if I've posted in the wrong place!
A couple of weeks ago I purchased a TL-WPA4220 range extender from PC World :-
It's a powerline extender and comes with 1 x base station and 1 x remote unit (i.e. it's a twin pack). A few weeks after buying it I realised there's an alternative version available (TL-WPA4220T) which offers an extra remote unit (i.e. it's a triple pack). Unfortunately, PC World don't sell it and they seem reluctant to take back my old one as it's not faulty and I've been using it for 3 weeks.
I just wondered if there's anywhere where I could buy myself an extra remote unit and use it with my original purchase (i.e. as if I'd originally bought the triple pack version)?
[Edit...] Just after my original post I found this link on somebody else's thread:-
Apparently it's supposed to link to a site for buying extra powerline adapters but it seems to be an invalid page (the invalid page links to some other page but that one just seems to be general info). If there's a link to a page for buying extra powerline adapters I'd really appreciate it.