Old GWR Loco Swindon discs

I came across these two discs whilst sorting the garage.
Can anyone tell me what they were for please, and if they are of any value/interest to a collector.

 

They are pay cheques for GWR employees so each employee would have their own ones. I believe the number is the employees number, not sure what the MT means, perhaps the persons initials or the exact department they worked for. I think they were hung on a board when the employee arrived at work and it somehow governed what they were paid. I can ask more tomorrow with someone I know who worked there. Not sure if they were just for GWR Swindon works staff or all GWR employees.

I don't think they are worth particularly a lot, they come up on ebay fairly often as ex employees seemed to just keep them. Probably more of an interest sentimentally if you know who they belonged to.

 

OK so I asked today some guys who worked previously at Swindon works . The tokens hung on the board and employees removed them when they arrived at work. The number is the employees number but they might get issued a different one if they went to work in another department. Then if they left for lunch or at the end of the day it would be hung back on the board. There were other tokens rectangle in shape just for pay day and also tokens put if they were more than 15 mins or 30 mins late. The MT is likely to be Missing Token ie if one was left at home or lost, issued as a temporary one.
Only workshop staff had them not other GWR employees.

 

Many thanks for your time, help research. Rather interesting.