The smokebox door shedplate here is 82A., Bristol Bath Road , which would quite possibly indicate a date for this image of mid. to late 1954 as " Pendennis Castle " went there from Stafford Road that year.
Subsequent reallocations would see " Pendennis Castle " at Taunton, Bristol St. Philip's Marsh and Swindon , the engine being initially withdrawn in May , 1964 following its spectacular failure at Westbury on the Special of the 9th. of that month , which , by a twist of fate strangely resulted in the engine's purhase and subsequent preservation , but that's another story !
Looking pretty much uncared for here 4079 , which had an illustrious history behind it , particularly in the days of the Great Western and the "Cheltenham Spa Express" , still would have quite a tale to tell, later being saved for preservation before spending a number of years in Australia but happily now undergoing further restoration by the Great Western Society at Didcot with its future secured and hopefully many more appearances on the main line .
An engine with a history if ever there was one !