I've always just put them in a plastic food bag when opened and keep them in the fridge.
The other week I had some cheddar that went mouldy within a few days and was still before its use by date. So I took it back to Tescos. They replaced it but the woman said I shouldn't keep cheese in a plastic bag but have it unwrapped in a tupperware box.
An online article I just found from Good Food Magazine said wrap cheddar in plastic or clingfilm.
I've always used plastic with no problems before. But now today I have more mouldy cheddar.