talk about steam driven technology
In 1967/8 the nav kit in the Herc was actually quite advanced - certainly space age in comparison to the Beverley. We kept the US C12 compass system, (possibly as would have been just too complex to change out, although more likely because UK didnt have anything remotely as good) and replaced the majority of the nav fit with UK products.
The Decca doppler 62M was fine, and fed 9476 and 9478 series solid state computers. These computers used Hybrid technology ie 'Analogue using Digital techniques' as the manuals described it. They were a vast improvement on the GPI 4 which was a real analogue device full of ball and cone resolvers and in use by much of the RAF at the time.