With 6779 newly ex works (with a pre 1957 crest and from 88B Cardiff East Dock), 5601 and 5568.6603 and 6635 are definately carrying 88A Cathays shed plates, 5601 and the prarie are harder to make out but also appear to be 88A.The pannier moved to Swansea in June 1956 so it will be before that date which fits with the leafless tree.

Cardiff Cathays looks remarkably tidy and free of the usual clutter so often associated with Motive Power Depots in those happy days of steam , and " Taffy Tanks " 6603 nd 6635 are two of the second and later batch of this design , displaying their valve covers above the cylinders carried within the main frames , a feature incorporated into the class by Mr. Collett from the original pre grouping Welsh designs of earlier times.
All one hundred of the second batch , like their forerunners specifically designed for use within the Welsh valleys and which dated from 1927 , were constructed at Swindon except 6650 to 6699 which were built in 1928 by Armstrong Whitworths at Scotswood on Tyne .
Popular with footplate men with good cab protection from the elements and often used on both freight and passenger duties the class would frequently be worked bunker first , especially on the Welsh valley branch lines where no turning facility was available at the head of the valley and its terminus.