Replacement altenator

I need to replace the altenator on my plus 2. The original came was a 65amp off a Rover but isnt stocked anymore. Can anyone give me done guidance as to a suitable replacement please?

I tried to get mine refurbished last year but was told it was not economical and was offered a replacement but it was about 40mm longer than the original so I cleaned it up and tested all the components and put it back on.Hopfully I’ve copied a link to the company I went to they are in west yorkshire.