How do I lower the pressure in my Vokera boiler?

Hi, I posted this question elsewhere but then realised this is probably its proper home!

I had my Vokera Compact HE25 fixed today but afterwards had to refill it. I managed to overfill it so that now it's running at about 2.5 bar when heating water, 2.7 bar when the central heating is on and then creeps up to nearly 3 bar when idle.

I know there's a release valve somewhere but I'm not sure where it is and don't really want to go taking the front of the boiler off as I have a feeling (from experience) I might make things worse.

Is there an easy way I can lower the pressure? (I ran a bath earlier and the pressure went down to 2 bar but now it's back up again)

Also, if there's not an easy way to lower the pressure am I endangering the boiler by running it with so high a pressure? I only just got it fixed today and don't like the prospect of another week without heating!

Finally, I don't suppose the boiler will regulate the pressure itself and gradually work its way back down to 1 bar?

Thanks for taking the time to read this and I hope someone can help