Did it work Wuffles?
One thing, sorry if it's teaching Granny to suck eggs and all that, but over here anyway, wine bottles are NOT a standard size - I've just checked some of our stock (in the nuclear fallout shelter you know - really) and of the first 20 or so bottles I picked up, they varied from approx. 73 to 87 mm dia. Add in the champagne and other sparkling wines, which in my sample went up to 96 mm dia, and there's quite a wide variation in size. And sometimes in the length too.
We use very simple & cheap stackable blow-moulded EP racks and they are standardized at 84 mm dia, which as above, is sometimes a bit small (so I've made some simple wooden "chocks"). But as above, these racks are ugly things, & NOT for display.
I guess it depends how you're going to finish your rack, especially the edges of the holes, but assuming a similar variation in bottle dia over there in UK, I'd suggest that 90 mm MAY be a wee bit small?
HTH
AES