hello, it is possibly Lynx pre-production prototypes XX469 or XX510, both conducted trials on the French FNS Tourville in 1972 and 1974.
the three window cabin door, differing tail boom and radome (without radar) would support this.
This is xx510 which is still used at culdrose as a flight deck trainer albeit in the now mid grey colours with mods but she still has the three window door the difference between the two pre production a/c was that xx466 had a blue spigot on top of the rotor head and crashed in 1972 due to a dis engagement between the tail rotor boom and main spar and was written off xx510 survives hope this helps
Can confirm with WD and FG86 it's XX510. I've got the original brochure from Westland Helicopters "Navy Lynx multi-role helicopter" Snell Printers, dated 1975. XZ166 also features in the brochure.