If you'll be giving up on the Linksys and looking for another ATA, I suggest you look at the Obihai range. I have used a Linksys PAP2, a Linksys SPA3000 and an OBi110. The OBi's have much more functionality and are reportedly designed by ex-Sipura people. (Sipura was bought by Linksys which was then bought by Cisco.)
Although OBi's main market is the USA (all the factory default settings eg tones and dial plans are for the US) they do also supply units with the appropriate wall wart in UK, EU and Australia.