I have to admit that I like it here. It seems more relaxed. The references to older gear brings back memories of when I started playing in 1962. That said, I do miss my friends on my side of the Atlantic such as your good self.
A 100w prototype could easily be built on the chassis of the bigger amp. It'll have all the holes needed precut.
For that matter you could just pull two of the output tubes.
On Talkbass there is a gentleman who I was fond of called Passingwind. I got kicked off the site for trying to warn people in the US what Trump was trying to do.
The problem is that my wife can barely walk and a flight to Manchester is more that she is able to do.
Damn Covid and the surgeries that got cancelled because of it!
Make certain sure that the amp will actually work on 240V 50Hz before you plug it in. A lot of amps aimed at the US market are not. If the amp will work on on 240V it will say so near the IEC socket. There may also be a switch that will need to be changed to allow for UK mains.
Not a matter of caring more, I think, a matter of just how many folks have tried both.
Aguilar are more of a premium brand and their speaker cabinets are well regarded.
Hartke are more run of the mill though they do get a lot of positive postings.
That seems a lot like carrying Coals to Newcastle. Use the amp as it was meant to be used. If you want to sound like you're using a Bassman then buy one.
Maybe here?
https://qcomponents.ca/products/b-c-14ndl76-8-ohm-14-500w-neodymium-3-0-voice-coil-woofer?variant=39705481314453¤cy=CAD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic
Failing that if the company still exists contact their customer service department.
Back in the late Seventies I built a monitor around a 12" JBL so I could hear myself in the harmonies we were doing. A little later I built a 10" version and that worked so well I built another. Finally I bought a IEM system and that worked best of all without the cost a a separate power amp to drive the monitors