A museum dedicated to only Ariels?
Oh please no.
That would be a straight recipe for endless discussions / problems with not only the Ariel owners but also Insurance company's and a plethora of governemental institute's and types, etc.etc.
Only possible way -I think- would be to start it yourself with your own bikes and no interference from others (exept your partner, which will prove enough interference...)
In the Netherlands there are a few examples like the Aermacchi museum from Jaap and Ellen de Jong and the American Motorcycle Museum by Max and Ans Middelbosch. https://aermacchi.nl/ https://www.ammh.nl/
There has been a initiative (long ago) from a few Dutch club members to arrange something like a museum by combining their collections.
It did not last long....(possibly because they where not married