Right chuzzy kits.....
Basically they are an enhancement kit board game (Sometimes called a Dog Bone, due to the shape), which plugged in to the mainboard of Electrocoin MK2 type boards (They don't work on MK 1's, same as the Concept / MAB one's), which gives the operator, several different games, based on the original electrocoin games (Due to legalities and to avoid confusion, they are NOT the same code as what Electrocoin use), like Bar-x, Big 7's, Red Bar etc.
The board can be used in BOTH the standard / slim / compact, and casino type cab, which uses the MK 2 system board.
As you have mentioned yourself, idea behind the kit, was to give the player, enhanced gameplay, like 9 / unlimited nudges, streaks, middle reel hold on jackpot symbol, nudges from 3 times O's on winline when held, flash wins, and so on.
For the operator, it offered flexibility and ease of game control, like being able to set whatever values in £1 lumps to various wins, as well as setting price of play from 10p up to 50p (Currently anyway, though I think this may have changed with the new £100 jackpot rules), and 3 different pre-set percentage rates, as well as enhanced game play data and security features, like recalling last win bank which is useful for checking short pay complaints.
As for MAB, chuzzy actually assisted in the making of these kits, however they somewhat differed in how they was designed and fitted (Tell tale sign you have a MAB, is if you see a small daughterboard fitted inside the cab on a fly-wire, which controls the JP / Price of play), also noting MAB did their own take of cabs, which again was based on Electrocoin’s..... As for the Concept version, they was an attempt of a copy (A very poor one at that!) of the Chuzzy / MAB kit, as well as making a flutter box version of the game (Which again was coded quite badly!), which was 2 or more bar-x type games chained together, with a random top box feature.
As for the man himself, I do directly know him (As does Ron over at MPU Mecca), as also knowing he has an arcade in Nottingham, which a few members have been to before, also noting that despite what others have said, the board does NOT breach copyright (It uses its own code for one thing, NOT same / similar, or adapted Electrocoin base code), and is still being developed to this day (I have the most currently released code, at v6.4, MK3).
Not got a pic to hand (I'm down at me mothers, otherwise I would take some pics of what I have at my place) of the actual board, though I do have the instruction manual here (See attached).