The Jag Jags were mostly bad in that era like all British cars due to industrial action and idiotic cost cutting which irreparably damaged the reputation of British cars, unfortunately....
A buddy came to town for a visit, and upon being told that the peculiar-looking tube amps were from England...

...marched straight over to one, picked it up, and peered closely at the shelf where it had been.
"Hmph!" he snorted, "can't be from England: it's not leaking oil!"
True story.