Thanks for that, the list I referred to it being included on is the one posted in the
https://www.secretprojects.co.uk/threads/british-ast-412-light-aircraft.3915/#post-312408 post 5, which I believe, if my memory serves right was published in Flight International
Not to self-publicise myself but...
Aviation Historian No.38 has an article by yours truly on the AST.412 contenders;
Shorts Tucano Vs Pilatus PC9: Replacing the Jet Provost in RAF Service.
It is an expanded version of the AST.412 discussion from
Teach for the Sky with a bit more politics thrown in and a little less technical detail.
The Flight listing is accurate - but then AST.412 was subject to all sorts of lobbying via newspapers and aviation press so this is no surprise. A lot of people were interested in how it might turn out. It was probably the last ever RAF super-contest that brought to together the big boys from around the world and the minnows who thought if they chanced their arm that riches would follow.
As to the Merlin/Martlet - I suspect, like Apophenia, that its origins are early than 1982-84.
In the late 1970s small turbofan and ducted fan trainers were seen as the next big thing to beat the rising fuel costs of the 70s. Scottish Aviation for example drew up the Sapphire using Bulldog bits and pieces with a Lycoming ALF101.
In early 1976 George Miles proposed fitting the M.100 with a Williams International turbofan. The M.100 G-MIOO (ex-G-APLK) was still flying so its possible a straightforward conversion was planned.
Miles claimed up to 870nm (1,610km) range on just 91 gal (413lit) of fuel and a unit cost of £70,000-£130,000. Miles also claimed that he had interest from El Salvador, the Philippines and a US/Swiss business group which was trying to interest the USAF. With some backdoor help by Donald Euan Palmer Howard, 4th Baron Strathcona and Mount Royal who had (and would) serve several government defence posts, the MoD took a look at the figures but threw them out. In 1978 BAe Prestwick was asked to assess the type as a potential BAe product but their assessment was equally unenthusiastic.
So it sounds like George Miles decided to upgrade from a Williams to a Garrett and adopt a tandem cockpit. But changing the entire forward fuselage would seem a drastic step, cutting about G-MIOO to that extent probably wasn't feasible so a new airframe would be likely I would think. Plus the aerodynamics might need upgrading and I'm sure the Garrett would need more air and so a larger intake.
