Looking back through my emails, the H5C1 went into production about April 2021. H5 sales look like 30 sold. Supposed to be 13 left in stock, so that's 43. I would have kept maybe 2 boards back. so that might add up. But there isn't 13 on the actual shelf.
EDIT:
Looks like there was a H5C1 preorder viewtopic.php?p=61969#p61969 that could explain it.. Different payment system.. So assuming 12 sold there, plus 30 via Stripe, thats 42 in theory. 6 left on stock.. So would seem to tally.
So more H5C1's sold than I thought then!
Thanks to everyone who purchased one and made the project happen! 
So there is now only 6 left in stock. I have them allocated in the store as 3 for UK sale and 3 for overseas shipping.