Well, I found the manual online but it said nothing about the water pressure. The system is working fine and the pressure is not dropping so its not panic stations.
I don't appear to have a user manual for this boiler, just the installation guide - so first question : is there a user manual?
Reason is that the pressure has dropped a little below 1 and I am about to have some plumbing done that will require switching off the water supply for a while, so...