8 & 9 speed out is interchangeable (generally), 10 is not. Don't waste your time trying to get it to work. Amongst my many skills, I'm a cytech 2 qualified bike mechanic...
If they won't amend the order (which reflects poorly on them), just order the correct one as well, and when the 10 speed fella turns up, return it under the distance selling regs, which give you right to return any item within (can't recall if it's 7 or 14 days) of delivery for a full refund.
I ordered a 10 speed Shimano Ultegra 6600 chain, £18.36 - what confused me I think was the Ultegra bit - which matches my groupset, but I neglected to check the block, when I realised my mistake I contacted them straight away - but they've refused to change the order.
Like you say - I'll order the correct one and return the 'wrong' one. Big thanks for all the replys - just so you all know it was RIBBLE CYCLES who provided such sh*te service...
S