I have a old set of LX wheels with centrelock hubs which I want to use with commuter tyres so I can swap wheels for the cycle to work .

Proper wheels have hope 183 rotors, and I have a couple of spare 6 bolt 183's.

So – can I get an adapter to convert the hub to 6 bolt, or will a 180 shimano disk work fine with hope x2s?

You'll get funny pad wear on them- the top 1.5mm will not wear down and eventually that stops the brake working. Best bet is to use adaptors- either to fit the 183 rotors, or a post mount adaptor to make the hopes fit 180s, which will be cheaper.