Virtually no HTTP/S throughput

[#1]

We reached our usage limit, so I put another £5 on, but things don't seem to have improved. Most webpage requests time out, a few eventually get served at least in part after some minutes.
ICMP and SSH performance seems to be fine, at least at the usual 3Mb down level, so I'm able to post here via an SSH tunnel.
Am I still being throttled?

[#2]

Hi richandsian,
I'm sorry to hear that you're having issues. You're not being throttled, everything looks fine on your account and your line looks fine too.
Can you try restarting your router to see if this clears things up for you?

[#3]

I've tried that a couple of times.

[#4]

Your usage has reset today, has there been any change for you?

[#5]

Yes, much better today.