When I first arranged the trip to Hertfordshire to view the items, I dreamt about discovering mountains of brand new add-ons and accessories for the Electron (RAM Cards? Disk Interfaces? Click cartridges? Heck, maybe even a pile of Electrons pre-installed with the mythical "Stop Press" add-on?).
However, despite scouring every inch of the location (workshop, shed, garage) in what turned out to be two separate visits, I'm sorry to report that there was barely a completed/assembled product to be seen, whatsoever ...

Though what we did find was a stack of empty/unpopulated Slogger PCBs, plus a good number of tubes containing various microchips and ICs (so my guess is that when the Slogger operation was winding down in the late nineties/early noughties, the intention was to make items to order ... though I'm doubtful whether [m]any items were in fact made/sold during that period at all, as myself and others [Hello Dave E!] found it IMPOSSIBLE to get a Price List out of Slogger around that time).
In addition to the PCBs we also discovered a box of early/prototype Slogger boards, which give an interesting insight into the "evolution" of certain interfaces.
There was also a large assortment of Roms/Eproms, many of which are bound to be "MIA" (so watch out for rom dumps on STH soon).
But perhaps most intriguing of all were the boxfuls of 5.25" and 3.5" floppy discs I found, some of which appear to contain source code for various Slogger/Opus products.
So even though my visit(s) didn't deliver exactly what I'd hoped for/expected, it was definitely worthwhile and I thought that some of you would be interested in seeing a selection of photographs from the "haul" (see below!).
And finally, I can bring news of one very exciting development: I sent a batch of PCBs for one of the most sought-after Slogger upgrades to a certain STH Forum member, and challenged him to build a new version of the interface, by populating the existing PCB with "modern" components.
By the sound of things it's gone very well, so I've a feeling that said member will be along shortly to make an announcement!

[Prototypes]
Here we have a bunch of prototype versions of the Click! cartridge, several prototype builds of the Slogger Pegasus DFS Cartridge (including one that's been assembled on a breadboard!) plus a few 'mystery' boards which I don't recognise (any suggestions?). Mystery unit 'B' has a 1770 on it, so it might be a [very] early prototype of the Slogger 1770 DFS Interface.