hi all, just completed my first commercial Asterisk installation … TDM02B, SipGate.co.uk and voipGATE.com providing trunks, mostly grandstream phones with PAP2 for analog/cordless. and an x-lite installation providing overhead paging 
i want to thank the assorted people here (and on the dev forum) for posting both questions and advice … without reading an awful lot of it i might have given up (or slit my throat !).
cheers !!
oh, and if anyone wants an SPA3000/Asterisk config that actually works in the UK inc callerid cough let me know. it only took me 2 days, lots of googling, and a very cross wife.
biggest tip … make sure (damn sure) that it’s PCI 2.2 before installing a TDM02B !!