Sorry but I have been out all day and have only just returned to base.
Axminster are aware of this and are doing some research now. I do not believe that it is a Lee Valley / Parf Dog problem at this stage - after all they are making Parf Dogs for track saw cutting stations and Axminster are utilising them in the Parf Guide System to create custom track saw cutting stations. Here are my thoughts but I must stress that @AxminsterTools
will need to let us know what they discover.
1. The fit of the dog shoulders in the 20 mm jig has been made deliberately as close as possible to slop free.
2. Yes, it is certainly possible for the anodising to be just a dash too thick - or rather the oxide is too thick. This is being looked at by Axminster and their anodising processor.
3. The deliberate tighter fit means that the dogs may need a little "wiggle" to get perfect alignment for them to pass through.
4. I would hope that Axminster can give some very simple guidance to users to sort this out which would not invalidate any warranty - something along the lines of what @squarecut
has done - but please wait for Axminster's advice.
If the fit of the dogs into the 20 mm guide block were loose then the accuracy might suffer.