For the past couple of days we've seen some intermittent issues on the servers that have led to the TA pages loading particularly slowly or, in some cases, not at all. This seems to have gotten even worse over the last two hours or so.
I'm currently investigating the cause and will post back when I have more info.
In the mean time I've shut down the mobile version of the site, just to eliminate that from the equation.
Apologies for any inconvenience caused!
UPDATE: All seems well now, I uninstalled some monitoring software I'd added to the web servers and it seems to have fixed the problem.