LTNman - Yep, G-BCBA Boeing 720-023B Invicta International - it spent a lot of time at Luton - it was looked after by Airline Engineering Ltd (Monarch). Here are a few more photos of diversions -
19761229 - HB-ISP DC-9 Swissair and G-BBME BAC1-11 British Airways, Heathrow diversions - Dave G.jpg
Dated 29th December 1976
19781231 - Apron scene with diversions Lufthansa & Dan-Air - Dave Gearing - Side [15].jpg
Dated 31st December 1978