There are no maker's marks or date marks on any of them from what I can see. I have used A/F for " as found " for 50 years.
Saltburn By The Sea From WHITBY - TPO - Railway Travel Post Office Plaque #TPO19
Sub Postmaster RUSWARP Whitby TPO - Railway Travelling Post Office Plaque #TPO13
DANBY From Whitby TPO - Railway Travelling Post Office Sorting Plaque #TPO11
EGTON Whitby TPO - Railway Travelling Post Office Sorting NAME Plaque #TPO3
Whitby GLAISDALE TPO - Railway Travelling Post Office Plaque #TPO18
Photo 6x4 Course of the old Whitby to Scarborough railway Whitby/NZ8910 c2017
