1960s Regional Jet Politics were fiendishly complex (ditto now, China, India, Japan, Russia, Turkey...) and Governments' funding (and it was nearly all Govts' money) had bigger aims than to build bugsmashers.
FRG Govt committed in 1963 to buy 13 HFB-320 Hansajets to resurrect a civil aero pedigree, and hoped that its 1962 military funding of Do.31 V/STOL transport might have Cityjet potential. Weserflug+Focke Wulf combined in 1964 as VFW; ERNO 61-4 scheme became VFW-614, soon losing its Lycoming paper engine. Nascent FRG Aero industry was wholly financed on military account and is best described as para-statal.
In 1964 Fokker launched F-28 and assigned its wing to (Nationalised) Shorts.
On 17/5/65 UK and France agreed to develop AFVG, BAC to lead Dassault on airframe, SNECMA to lead BSEL on M-45G.
UK Govt. funded Study, 11/65-4/66 by BAC and by HSAL of a Big Twin for BEAC. France saw the same market prospect, (Nationalised) Sud Avn. scheming Galion and talking with their Concorde partner BAC, Breguet/Nord Avn. talking to HSAL. France and UK both wanted to bring FRG onboard AFVG and the Big Twin: FRG had the obligation to offset the foreign exchange drain of Visiting Forces, US (hence F-104G), UK (hence those odd 1957 choices of Gannet, Sea Hawk, Sycamore, Pembroke) and France (Noratlas, Magister, Alouette).
HSAL+Breguet/Nord plus VFW+HFB submitted HBN-100, BAC+Sud Avn, Galion. FRG provided Launch Aid for VFW-614 and assigned its nacelles to Short, its engine to be BSEL leading SNECMA on BS.127/M-45H, with DM50Mn. FRG Launch Aid "counting" towards £ offset.
The rest of 1966 and all of 1967/68 were diverted by AFVG/MRCA, Space (ELDO), and the Big Twin: all of this was politics - as seen by UK, it was all to do with trying to join the EEC. VFW-614 was assigned for production involving (the South Group, re-named) MBB and Belgian SABCA/Fairey; from 10/66 Rolls Royce owned the engine, but did not care for it after AFVG/M-45G was chopped 29/6/67. The 3 Nations confirmed A300, 25/7/67 with RB207. Only VFW-Fokker (formed 1969) now cared for VFW-614 (until Fokker divorced in 1980 and launched (to be) F-100/F-70).