White Horse 1952
I saw a bottle of White Horse bottled 1952 By Appointment to His Majesty The King sell recently (early December) at auction at McTear's for £190.00. According to their notes, the label was in good condition, there was a minor scratch and the back label was frayed. You can always check any of these companies for a value: McTears.com, Bonhams.com and onlinebbr.com
Also, thanks for posting photos - although they are a bit hard to see / read.
Keep us posted on your findings!