Thanks for your replies.
Spoke to britpart today and part is not available from LR as they have none in stock and unable to say if or when any will be available.
Other suppliers report none available as well so I was wondering how long this this has been the situation and if the part will ever be available in the future.
I have not gone down the breaker second hand route yet as reliability is the primary consideration as any replacement is likely to be as old and potentially unreliable as mine which may be responsible for random infrequent electrical problems which i will list in another thread later.