There is an urban exploration site called 28dayslater that has pictures of the inside of AJ Parker's premises some years after they ceased trading; there are loads of SKN action No4s just laying around rusting. I heard the premises have since been cleared, so anything pictured is no longer there.
Were some of them made by AJ Parker, or did Parker's just buy a load of them?
Report - - Alfred Parker Ltd Gunsmiths, Birmingham - June 2010 | 28DaysLater.co.uk