The Parker Hale - as per Post #2 - with Parker Hale sights. I have one marked on top of barrel as made for the 1969 Palma Trophy Competition - was held at Connaught Ranges near Ottawa that year - PH made up 60 of them for that shoot. The barrel on this one is heavy - as shown in your pictures. I have read that this 7.62 NATO 1200 TX was the basis for the Canadian C3 military sniper rifle - all of which were "re-done" by Parker Hale to become the Canadian C3A1 rifle. Many of the C3 parts were then used on orders to Parker Hale by Central America countries.
Inspect the rear sight on that PH 1200 TX closely - on rear face of the horizontal cross bar, this one has stamped "PH5B2" - the "2" is in a taller font - as if added to the first part - I had presumed that was the model number of that Parker Hale rear sight. The rear face of the mount block - facing the shooter - says "Parker Hale Made in England". The sight mounting body has an extension and leg / foot - so that rear sight mounts into what could be used as rear scope base holes - same spacing, etc. as the PH 28 rear scope mount base. As received, this sight had a PH60 eye piece installed - is six choices of aperture size within that eye piece. Is hard to tell from your picture, but seems as if there is no eyepiece installed?
In the book "The History and Records of the Palma Match" by Colin C. C. Cheshire - page 4.128 - says that the PH rifles used in 1969 were equipped with Parker Hale "582" rear sights - the "B" possibly being misread as an "8" - and that the front sight was PH 5M 159. I can not find any marking on this front sight at all - it fits correctly to the base on the rifle barrel, but has no markings, not even the PH logo.
I have tried to ID the shooter of this rifle in that 1969 shoot - no luck, but I have corresponded with a fellow who is son of one of the Canadian shooters that year, who still has the PH 1200 TX rifle that his Dad shot at that competition - except for mods that some subsequent owner made to the butt plate on this one, the pictures of his and mine appear to be identical - so is two known to me, out of the original 60 made for that shoot. No doubt hundreds or thousands more were made for other purposes.
As per Post #2 - I can not help about that Model 70 - I believe similar was used in Palma shoots in USA in 1968 at Camp Perry - but likely were also used many other places and purposes. That book mentioned above says the Win Model 70 used in that 1968 shoot were equipped with Redfield aperture sight, and were stamped "Palma Trophy Match" on top of the barrel. For some reason - perhaps some types of competitions(?) those target Win 70 had a "charger slot" cut into the top of the rear bridge - as if charger re-loading was used? I also had a gunsmithing book from that era, that included a template for cutting that slot into a "normal" Win 70 receiver. Is interesting to see on those two rifles that they might have had different thoughts about using a shooting sling, or how to "sling up" - is possible that the "hand stop" on that Win 70 might be installed backwards in those pictures ?? But I have never competed, so that might be a perfectly acceptable arrangement, as is?
You might want to appreciate that in those days, a "Palma Trophy Competition" was shot at 800, 900 and 1000 yard bullseye targets, with those rifles - for many years using ammunition provided by the host country, as were the rifles. Is done differently these days, I read. But, was no artificial rests (so no sandbags or bipods) and no optics - no scope. There are several Palma shooters, former Team Captains and Team Coaches that regularly post to CGN. If I am in error, I am sure to be corrected shortly, I would expect.
I wish!! 
