After some initial searching, it became obvious that, being separated by thousands of miles, the legal option could be costly and time-consuming itself.
I then had a brainwave - Bruce has no motivation to fix my amp. Would a direct financial incentive tip the balance? Worth a try...
The email response was almost immediate and worthy of any English cricketer's "straight bat" defensive stroke - see part 53.
I was thinking about this... there's no motivation for you to finish fixing my amp because as soon as you go back to working on it, it's costing you money, especially since you offered to waive the upgrade and return shipping costs back in October of last year. With a finite amount of your time available, it's more appealing to spend it in ways that actually generate revenue and will be "keeping the lights on" as you put it in a telephone call on 3 March this year. As a side point, you clearly haven't put a value on your reputation had I chosen to comment publicly on the circumstances of this warranty/upgrade work.
So here's the offer: I pay you $1000 to finish the work on the amp as discussed and ship it back to me by - say - 31 July, which sounds like a reasonable timescale to me in view of what has gone before. Compared to the $235 which I was otherwise expecting to pay for the used case and new power tubes, you're still "quids in" as we say over here even after you've paid for the return shipping.
Why this sudden initiative? After much consideration it felt like a pragmatic alternative to putting the equivalent amount of money or more into the pocket of some Arizona lawyer and breaking out of this tedious waiting game that way.