I thought that, and the locos on that branch were R1 Class? But any photos I have of R1 and R class locos have some fancy work on the front of the smokebox. Maybe that was just the R class and these are the R1s.
They are definitely of SE&CR origin - the shape of the smokebox and cab are in the SE&CR design style. Looks like an enlarged P class, but I can't find any information about them!
Regards,
Dan
If at first you don't succeed, destroy all evidence that you tried
There are two different types of R/R1 that were taken on by the amalgamated railways. There is the LCDR R/R1, which was an 0-4-4T engine, and there was the SECR R/R1, which was an 0-6-0T engine. It is the latter that appears in your pictures and that was the banker on the Folkestone Harbour Branch at the end of their lives.
Regards,
Dan
If at first you don't succeed, destroy all evidence that you tried