Old Worcester 25Si repress urine after rad bleed

[Dingerbellmbe]

Hi there, help needed. Moved into our new house which has an old Worcester 25Si. We had a new radiator fitted but the "plumber" didn't repressurise the system so I've bled the rads but the pressure has dropped and I do not know how to top up the pressure. I can't find a tap or indeed a manual.
Any advice please.
Cheers Chris
Sorry for the thread title, predictive text strikes again.

 

[SteveWannadoGas]

Have you sorted it now?

 

[Dingerbellmbe]

Thanks guys but it's a really old boiler in a very old and neglected property. The boiler is in a cupboard with pipes leading up to it but no sign of a "filler loop". No taps apart from a small "online" tap that looks quite newish. I've bled most of the rads but the pressure is down to 1.5 bar so there isn't enough pressure in the system to even bleed one rad in the upstairs bedroom. Any suggestions please.

 

[ShaunCorbs]

1.5 bar should be enough to bleed rads time to get a gas safe engy out