Hmmm, just tried the pings and it worked on all modes, so there must be some sort of connectivity.

However, I updated the catalogues on fapman and the progress bar doesn't move on 3G until it changes to 3.5G. Likewise with gpodder, updates totally stall while on 3G but rattle through on 3.5G.

Is there a way of forcing 3G rather than 3.5G to help diagnose this?