This board has the facility to instant message those who are on it. It often happens that the person you instant message will have gone by the time you send them their message. It doesn't matter, they'll receive their message the next time they open the board
All you do is go to the top of the forum index page, and see who is listed online under the V slash heading and line that says Forum West Yorkshire Truth Campaign
If you want to message someone who is online you click on their name - it's simple from there
If you receive a message centre screen from someone, it will tell you to click the button to answer. This will produce nothing
You still have to go to those online and click on their name  to reply

Yeah, annoying that when it says to click to reply and then disappears. I'm gonna click it where the sun don't shine next time if this continues.

I'll put it as a topic on the support website and see what transpires. Personally I don't find it to much effort to move back to the person's name and click, though often they've gone by the time you press send.
Which is always a bit of a pissoff