You need to change the time in your Bravenet account.
After logging in click the "membership profile" button on your Bravenet account page. There you are able to adjust the time. This will change the time for all your Braveent services.
Judging by your email address I assume that you are in the UK
Two possibilities. Unless you adjust the time zone in your account the forum will display the time at Bravenet's location in western Canada.
If you mean that you had set your time zone and suddenly it is an hour out then that is correct. Bravenet can't cope with daylight saving time changing on different dates in different countries. They will adjust your account for BST a fortnight early as USA and Canada change their clocks earlier than Europe. It will be correct on Sunday morning.