"The remaining fleet was upgraded to HC.2 standard, only within the last 10 years, at an exorbidant cost. Some sources suggest the OSD could 'slide' 10 extra years though!"
£400m for 20 aircraft which gave 10-14 yrs of extra service, whilst out-lifting the Merlin in Afghanistan was a bargain!
to re-engine the Merlin was around £800m...