Hi Jonny
Reckon you are right with the location - that's an Up train so heading east on the up fast
Based on the reporting number and preponderance of Choc/cream stock I reckon that's 1959/60 ish - see discussions at http://www.rmweb.co.uk/community/index.php?/topic/13298-brw-train-reporting-numbers/page-3
Also Sudeley Castle had a Collett tender from at least 1962 - that's the earliest picture I can find with that tender, she went for scrap in 64 with that,but did have a HAwkesworth tender earlier - will see if other pictures come to hand
FOr some reason I feel this picture looks familiar - I do wonder if its a Richard Blenkinsop , copy perhaps?
Phil