Call an engineer - have it properly repaired and serviced.
British Gas have a tendency to up-sell - they may try to get you to buy exta services from them at top dollar - best to give the work to a reliable independent trader.
The RD1 boilers were last made in 2004
Peccavi
October 2009
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.