How can I mend my potterton puma 80?

My puma 80 after I draw hot water makes a terrible noise then the pilot light goes out. If I swich the standby button off before I switch off the hot water I t avoids the pilot light going out . I have had heating engineers round who just want to give me a new boiler it's apparently to old after 10 yrs . Surley its just a new part any suggetions.