ww2 service info please

I have just been looking at a couple of (?) bakelite discs with RAF stamped
on the back . On the front there is a service number and the serviceman's
name - in between those there are the letters METH .
Please could someone tell me what they are likely to be and what the letters
METH signify ?
Ta everso :-)

datasmog...

You don't say how big they are but a couple of shots in the dark.
Uniform buttons, although having your name on buttons is a bit poncy
even for an RAF bloke.
Or identity tags. Wearing round the neck for the use of.

Otherwise, ashtrays?

Gareth...

This site may help you Boo

Anita...

there was a place called Metheringham shortened to METH

BunnyHare...

Hee hee well it was Boo who asked the question not me:-)
I do know Metheringham though

...and more specifically this one to find out about the squadrons, the
aircraft they flew and where they flew.