It's an Austin A40 Farina all right, registered LXG 999 and, inherited by a Martin Pickering from his grandfather.
He made absolutely all sorts of modifications to it, too numerous to mention here, for instance a Ford Anglia rear axle, Austin Allegro headlights, Lada seats, Sprite disc brakes, and finally a Morris Marina 1.3 engine bored out to 1340cc and mated to an MGB gearbox.
The car was featured in 'Hot Car' magazine in about 1976.
It has subsequently been scrapped.
Here's a rear view:
