Unless you really know what you are doing, I would seriously consider buying from a good local bike store (LBS) like
Condor, rather than going for an online bargain.
Your LBS will make sure you get the right size, let you try the bike before you buy, set it up for you, and probably offer free servicing during the first year.
Unless you are absolutely sure about the size you are ordering, buying online could be an expensive mistake, and you could spend more than you "save" trying to sort out all the subsequent problems.