Good Moring Doctor Ken
An excellant diagnosis
It is indeed the Vickers R.156T (aka Vickers Type 799 and SP.4)
Operational Requirement 330 (OR.330) started life as a 1954 requirement for a high altitude, high speed reconnaissance aircraft.
The gamble of alloy manufacture precluded the Type 799 at the first stage as it could never increase it’s speed. It’s range of 3000 miles was also inferior to the contract winning Avro 730’s 4250 miles. Soon after awarding the contract, the requirement was updated to include a bombing capability. The contract was scrapped with the Bristol 188 technology demonstrator flying, and the Avro 730 prototype half built.
Skytrain10 has control 