I'm going to be fitting 6-8 of these and my budget is limited. Do other
manufacturers make modules that fit, and if so where's the best place to
buy? Online ordering would be ideal...

I got mine from netshop. Patch cables from a quid. Populated double RJ45
faceplates from less than a fiver. All including VAT. You might be able to
buy MK faceplates and find cheap modules to fit. You'll have to do serious
checking on dimensions.

Christian.