The d/d buses from First shown here- were bought by Capital Buses in London for London service. At the time, the company was seeking to expand, so they needed new buses for the new contracts they won. So they got a very good financial deal from Dennis at the time; most of the buses were bodied by east lancs, some by plaxton/nc bodymakers.
They served in East London, and appeared on almost all routes there- first in the striking yellow livery, then in the modified red/yellow livery. They were replaced by low floor buses [the TN tridents], and were recycled for further use in other First companies outside London.
I have some photos of them in their prime- in London service, and I'll try to scan some later today
