Marvelous, what a wonderfully obscure present…
How about:
"Darling, this is an excellent present, and something I really want to do in a few years time when I've mastered some of the other finer points of my trade. But, at the moment I really want to focus on my health and wellbeing, that being my bike and the fitness you then enjoy… any chance we can cancel it this year getting the cash back? We can then re-book it in a couple of years time when I'm more prepped for it"
So, not actually saying it's cr@p but at least getting yourself out of the hole.
Then, one drunken night in a year or so you can mention how it was a terrible present and the emotional pain will be less (the physical nutsack kick may still smart).
Just read your last post.
Well sorted.
Andy