Hi Keith
I asked about Dave on the Halton FB page and have had an initial response from 3 people.
He was in 219 entry which means he would have 'joined up' in Oct 1970.
219 was a Craft Apprentice entry which meant a 2 year course and normally passing out with the rank of Junior Technician (J/T).
Apparently his initial posting was to RAF St Mawgan (Oct 1972) which ties in with your info,if any more details are forthcoming I will let you know.
Could you please pm me details of Davids sad passing and I will post them on the FB page.
rgds LR