I did some Chumbley merchandise a few years ago and I regularly return to them as the subject of alternate merchandise. There were part of a regular troop of alien robots that were seen as attempts to duplicate the success of the Daleks during the early years of the series. Needless to say, like the Mechons, the War Machines and the Quarks, they failed to make much of an impact. They haven't been awarded the honour of a figurine by the Doctor Who Figurine Collection. Shame!
Here's a few more items from an alternate universe where the Daleks were overtaken by the success of the cute little robots from Rilla.
If these examples of fan sadness have moved you to pity, then you might like to purchase a new warming cup of coffee for the poor soul who created them. You can do this via his Ko-fi profile. The link is here. Thank you.