Hey Chris,
the hand trim router Makita RT070x is generally sold with a 6 mm and a 8 mm collet in the whole world, it’s only in the USA and in Canada that you get a model with an imperial ¼″ collet (and only in North and Latin America and in Japan you have girly power)
(however in Japan where 100 V domestic power is usual, there are only Makita hand trim routers without cord anymore (LiIon rechargeable battery on brushless DC motor:
).
I have a Makita RT0702 here, I can show you a picture of the 6 mm and the 8 mm collets in the package if you like.
You should be able to get the 6 mm and 8 mm collets as replacement part. I remember a forum user got them at eb*y or somewhere.
See also
PS: Edge finders