Thanks for the comments so far.
I was North and considered it an automatic pass, not even close. But then I like this double to show majors at least 4-3 which is not everyone's cup of tea I realise. South was aware of this but it is only the second time we played together in years so I don't expect him to feel unusual pressure to balance. I don't consider his hand rubbish in this context (it has some shape and controls, partner must be near opening strength and have some diamonds) but it certainly is weak and I can understand a pass.
What really pushed me to look for a reality check is that 1
♣ making turned out to be a rotten score for us: just 37% at national level over 249 tables, which would have been 24% had they made +1 as they should. So at least one player at the table was on an unusual wavelength compared to much of the country.
At 17 tables NS made a contract, at 69 EW made -70 or -90. At 93 tables EW went down -200 -300 or even -400.
Playing 20-21 2NT one might upgrade the West hand, and of course some pairs will be playing strong clubs. But I think most Wests will have bid a non-forcing 1
♣ here and I guess some Easts would stretch to respond despite the vulnerability. So maybe it was East rather than South who started the squabble that often led to EW going down hard.