the difference in colour is probably more to do with the photo than the actual flower. It is a mauvey colour. If it is Blue moon then it is a genetically stable form. Buy from a good grower to be certain of the quality of the plant. Beales of attleborough are a good supplier, though not hat cheap.

The bluer the flower photo in the catalogue, the less inclined I would be to be from that supplier.

Take a look at its successor "Twice in a Blue Moon" bred by Fryers roses (Knutsford, Cheshire) - reckoned to be a stronger/more resistant variety. If you're not too far, a trip to the Blue Diamond GC at Evesham Country Park might be worthwhile as they are stockists of Fryers Roses.
Following my recent experience with the wrong camellia, I would suggest that if this is a rose you particularly want then wait until you can get one in bloom rather than risk falling prey to the mis-labelling bug.

Thanks everyone - I thought it might be that -the colour variation of pics. I shall def take a look at 'Twice in a blue moon' before I order from The Daily Mail selection of roses they have on offer.