high reading on pressure gauge on rd628 worcester boiler?

I understand from the Instruction Manual that the pressure reading should be below 2.5 bar. However, ours usually reads between 3 and 3.5 when the boiler is on. I have bled the radiators twice, which has been suggested, but still have the problem. The wall beneath the pipe where steam is escaping is getting very damp, and there is also a permanent puddle beneath this which can get very icy.