I have recently replaced a radiator and topped up my baxi boiler pressure. Then noticed a leak coming from radiator (only small) and when checked the pressure was at 3.5. I used the prv (red cap) to release the pressure and now the prv is still dripping, not loads but it is causing pressure to slowly drop on boiler! Also there is still a very small slow leak coming from radiator on one side. What is the problem? Do I need to get someone out to sort the prv problem?