The answers are as follows:-

EdW was right stating that all the ships mentioned used the COGOG system of propulsion.

The Type 21 used RR Tyne's and RR Olympus (affectionately known as Ollies)
The Type 22 Batches 1 and 2 used RR Tyne's and RR Olympus (affectionately known as Ollies)
The Type 22 Batch 3 used RR Tyne's and RR Spey's

However the answer I was looking for is that the Type 21's could use either the Tyne's or The Ollies not a combination of the two.

The T22's Batch 1 and 2 could use both the Tyne's and Ollies at the same time.

The T21,T22 and T42 all used a shaft that at all times rotated in the same direction and the direction of the ship was controlled by a Controllable Pitch Propellor (commonly abbreviated to a CCP)

For those that are interested there are some very good videos on the Tube regarding ship propulsion by a guy call Olly Epson who was an MEO in the RN.

I will give a few more hours for people to have a go at answering then I will post the answer along with today’s question

Well the first line of EdW’s answer is correct

All these classes used the COGOG system🤔
But the 21 class used different turbines to the latter two.
The company that I used to work for made heat exchangers for all these classes.

Hi Pat, Just sent you a PM. Best wishes Tim

Surprised Doug has not had a go at an answer

Have I posted a question that no one know the answer to ?

Again a two part question

The Royal Navy Type 21 and Type 22 Batch 1 and Batch 2 Frigates used the same drive system, with one major difference - who can tell me what it is ?

The Royal Navy T21, T22 and T42 used a unique feature in the drive chain, who can tell me what is is ?