S5: 1950s' RAF was not Brit-mounted. Avionics was intertwined, UK/US; ADEN gun was German; aerodynamics was German/NACA as much as RAE; fabrication was muchly off Cincinatti tools, and production of Hunter, Canberra, Valiant, Javelin, Gannet....was heavily subsidised by Uncle Sam.
UK has never been wholly techno-sovereign in Aero. Many UK piston aero engines began as French licences. Aerofoil sections might be NACA or they might be Gottingen. All, bar none, material which we turn into kit is imported.
A to OP's Q is that, no, it matters not who invented the kit we use. See Israeli Air Force, fighting on US and French craft, never on indigenous designs. What matters is whether we have access to spares, tools, (now code) to sustain readiness. Starting with 1941 Lend/Lease, UK appointed Sister Firms as Design Authority, competent to keep kit flying even if Supply was disrupted by hostile action. Now,to ensure operational sovereignty v. commercial or political action, Ministers have stressed, on (US) F-35, access to source code, and on (Israeli) Watchkeeper, Design Authority into a UK entity (which happens to be French owned).