I remember Mach I don't think they ever? talked about a 4MB upgrade for the A300.
Watford were the first to talk about it, but it kept getting delayed so we at CJE developed one and were the first to market!
It was I think the most profitable product we have ever done!
I think Mach did start to develop most if not all the products they announced, I recall they tried picking various peoples brains when they ran into difficulties, the particular one I remember was their IDE interface.
It was run be a number of recently graduated youngsters.
I don't think they realised what was needed to take what would be acceptable as a Degree project out into the commercial market.