Apologies for the slight delay as it's taken a little while to locate the badges and get some reasonably clear images together.
I've attached an image of three makers' marks believed to be fake. Interestingly they are all different. The Grove font is larger while the Smith & Wright and Jones and Jason marks have different kerning. This potentially indicates that they originated at different times and/or from different sources. The Grove and Smith and Wright sliders are as soft as butter while, as previously noted, the Jones and Jason example is very hard brass. Normally, I would caution against dismissing different variations of makers' marks out of hand, if they don't match known examples, but on this occasion, given the badges they have frequently appeared on, it's fairly safe to assume they are dud.
The Marples & Beasley marked Para Reg beret badge is more interesting and I have attached a number of images of it. Received wisdom is that M&B produced mainly Officers' badges at the time and ORs' examples (if indeed they were made) were not marked on the slider. (This obviously pre-dates the later anodised badges which were stamped)
The only other M&B mark I have from a similar era is on one of their silver plated OCA button back lapel badges. I have attached images of this although they aren't particularly clear due to the location of the mark and the patina on the badge. The mark is embossed on the casting, rather than de-bossed by stamping, and is slightly asymmetrical with the 'B' of 'BIRMINGHAM' under the 'P' of 'MARPLES' and the second 'M' of 'BIRMINGHAM' under the 'SL' of 'BEASLEY'.
Having examined the M&B marked Para Reg beret badge again (including under very strong magnification) I believe it is a good pattern and original. The hard brass slider shows no signs of having been replaced and the solder work is of a very high standard. There is nothing to indicate that it has been reworked in any way. The M&B mark doesn't appear to have been added later. Notwithstanding this, it could be a high class forgery. I can't obviously say for certain it's an elusive original M&B marked ORs' badge but I've had it over 20 years and it's certainly a plausible candidate. Whether it will survive Alan O's keen scrutiny is another matter
Genuine maker marked KC ORs' Para Reg beret badges are thin on the ground but an example with good antecedents is the Gaunt factory conversion of a batch of badges from lugs to sliders. You can see the original position of the lugs in the images. These have featured on the Forum previously and I have attached images of my example.
Graham