Well, if this benefits anyone … I had continual problems with disconnections (see above) and I tried everything GW2 suggested inc. forums and had my ISP check their side which came back ok, fiddled with the router etc. … I thought my mac may be too low spec (2006) but in the end brought home my dongle (3 network) where it was running fine on my work computer and duly worked fine on my home mac … so it seems my problem probably lies with the router – a Belkin F5D8633-4 – a quick google and it looks like a common problem. Plus Belkin haven’t updated the firmware since 2008! … I now plan to either buy or try a new router … if that fails I’ll try getting a BT line test.
BTW the game runs fine on 2006 Imac – lowest graphics settings and can get down to a few fps when lots happening but generally running well at about 25-30 fps.