It is always interesting to see the posts about copying diecasts from other manufacturers and the 'negative connotation' it carries against the 'copier'.
Thanks to @juantoo3 we now have the Budgie casting list, which can be compared to the Matchbox line up from the same era. (I dont have the time at this moment, but added it to the to do list for future follow up. Unless, somenone elses want to make the comparison in the meant time.)
My theory is that if there is an overlap with Matchbox castings it is because they were made in the same factory owned with Rodney Smith, as is already noted above (and other local factories used by Matchbox) at essentially the same time frame.
And second, that the Matchbox castings probably came ofter the Budgie/Morestone castings were initially offered.
Off the top of my head, only the two VWs had counterparts in the Matchbox line, and there are telling differences, so I don't think they are direct copies. Certainly possible they were "inspired by," but I would question actually copying. The Landrover is completely different (larger) than the Mbx, the Bedford delivery is larger and different, Mbx did not have a Maudsley Horsebox or either of the BSA motorcycles with sidecars, or the Austin Mail delivery or Austin phone repair truck. The Budgie Cooper-Bristol racer is quite different from the Mbx open wheel racers of the era, and the Mercedes racer I don't recall a Mbx counterpart. Mbx did not cover the Wolseley Police car or Austin Countryman...the model line ups were so very different between Budgie and Mbx, it really is only superficial similarity easily noticed if one is familiar with the models. At a glance Budgies certainly have a similar "vibe" to Moko era Lesney Mbx, but that is where the similarity ends....I really don't believe there was any copying or transfer of tools. Perhaps...really reaching here...they may have sourced wheels from the same contractor as the wheels for the most part seem to be very similar, but that would have to be checked too because I know I don't know the "anorak" details of Moko era wheels or how they compare directly to Budgie, but that is the only significant similarity I can think of between them. Far easier to mistake Benbros and Budgie than to confuse either one with Lesney from the same era once the model is in hand.