Martin, the 122 didn't go via Hawkhurst - you're probably thinking of the 57 between Gravesend and Hastings, which did.
The 122 ran direct from Gravesend to Tunbridge Wells via Borough Green and Tonbridge, then continued via Crowborough, Uckfield and Lewes to Brighton.
In answer to Dennis's question, I seem to recall an article by Paul Gainsbury in an old issue of Buses Extra or Classic Bus some years ago, but
it will take a little time to track it down - in the meantime, we covered the subject briefly in a thread on this group last year entitled "Service 122 Gravesend to Brighton", which you will find here, so I hope this will provide some of the answers you are looking for:
https://bit.ly/2HqfFTK
Derek J