Meltonian has a convoluted history going back to the early 1900s, which you can read at the link below.
It no longer makes retail shoe care products, though you might find a few offerings on eBay.
Do a search for Meltonian, and this is the result, as you've no doubt found John:
https://www.amazon.co.uk/Meltonian-S.../dp/B00KUREWCA
When their Watford works was shut down (early 60s?) the manufacture of Meltonian products was transferred to Reckitt’s site at Hull. However, in 1991 the Meltonian brand name was bought by the Sara Lee Corporation, along with Reckitt’s entire UK shoe care product portfolio. The Meltonian brand name is now licensed by Italian company Iexi Srl for bulk shoe trade leather treatment creams (who also make and sell trade products under the Wren’s and Propert’s brand names of old).
https://www.blancoandbull.com/boot-c...brown-and-son/
Search on Wren shoe-care products, and disappointingly, no coloured products:
https://www.amazon.co.uk/Wrens-Leath.../dp/B01ERPXGNQ
There is now only one UK shoe care product manufacture in the UK, namely, 'Cherry Blossom and Grangers International' who used to manufacture products in Alfreton, but in 2019 relocated to junction 29a of the M1, to new purpose-built premises with new 'state-of-the art' machinery, so they seem to be very much in business.
Their range of products can be found here, but not unsurprisingly, are all out of stock at present as the factory is closed for the time being due to pandemic restrictions:
https://cherryblossom.co.uk/products...ng-shoe-polish
Like Meltonian, Cherry B has an interesting history, but that's only of academic interest - it doesn't solve the problem of how to find suitable products right now.
https://cherryblossom.co.uk/pages/our-heritage
Not much help at all, but I guess there will be all sorts of products that would fill the bill, if they can be winkled out in a google search.
Hope these notes are of interest.