If I recall correctly some astra domes were purchased for the H models, for what reason I know what but I was also told that they had to be stowed in a special container when not being used because they were so expensive.
The K models were going down the line at the same time as our E models and they had lots of RAF mods including their unique floor. The Smiths auto pilot was a disaster with aircraft having to be hand flown for the first part of their service. Radio equipment was RAF supplied as were flight handbooks.
The K model was worked hard with too many AUW for take off at 175,000 lbs, this figure was a maximum overload but the centre section and wings were not designed yo be continually flown at such a weight. If memory is correct they also had the dash 15 engines with more HP, shame we had not the same mod.
The K model would have up till the arrival of the C17 been the best transport aircraft the RAF ever had, shame it was not treated a bit better would still be capable of more service.
regards
Col