OP - you asked about stocks - I no longer have either, but within perhaps past five years on EE I had bought a heavy forearm that was apparently "prepped" commercially, and separately, a L42/Envoy hand guard. So with receiver ring and stock band, would be able to assemble to a "wanna be" Envoy, I think?
That forearm had similar appearance / profile to the one on this PH 1200 TX - heavy, broad - had 1950-ish type epoxy bedding installed - I do not remember if bottom surface was set up for hand stop or not - I seem to remember that forearm was actually for a Parker Hale T4 rifle (or similar name for it). I am pretty sure that forearm was not meant to use a hand guard - so would likely need to find appropriate forearm - target style - to use with hand guard and bands.
Hand guards were made by a specific British maker - C. Moon? - that one had that stamp - for heavy diameter barrel, not for standard profile 303 British milsurp barrel. So, bits and pieces were made and sold, back in the day - no clue where you could buy them today??
At least one former mil-surp stock here - I do not remember which action it was for - it might have been originally for a Swede 1896 or similar - was "slabbed" - slices cut off sides of forearm - then more-or-less matching wood blocks glued on and entire forearm re-shaped to look like a target forearm, although inside inletting was all military. Some wood worker did a very good job joining those blocks to that forearm - made it fat and heavy and wide - and very nicely re-finished.
Go here - scroll down - various sketches and photographs of PH T4 and others - might be what you have in mind??
https://www.rifleman.org.uk/L81A2_Cadet_Target_Rifle.html