Thanks, it's certainly not obvious it doesn't come with caddies, the pic has them in! They've confirmed they aren't included.
Currently doing some rough estimates...
Around £450 for a SUPERMICRO 6027R-E1R12L 2U 12 BAY SERVER
M/B - X9DRD-7LN4F-JBOD
Xeon E5-2660 2.2 GHz 8-Core (and could add a second for about £50 from ebay)
48GB DDR3
includes 12 caddies sourced from ebay
11098 Passmark with one CPU
Arounf £390 for a Ryzen upgrade to current tower
M/B - ASUS AMD AM4 Ryzen PRIME X370 Pro
Ryzen 5 2600, 6 Core, 12 Thread, 3.4GHz
16GB (2x8GB) Corsair DDR4
13529 Passmark
So... Ryzen is cheaper, has better single thread performance and is lower power (65w cpu versus 95w).
SM has boats more (slower) RAM and space for a (cheap) second CPU.
Ryzen will be quieter and the AM4 socket means I could swap in an upgrade in a few years if I wanted too.
As this is going in a cupboard so the noise isn't really an issue... its a close call.