In reply to Rog Wilko:
My wife buys plants from Crocus, the RHS website matches the Crocus website, RHS use them for all their plant orders; plants are good quality, come well-wrapped, are healthy (if perhaps a little small) and they grow well. One supposedly pink Achillea which turned out white was resent as the proper pink with profuse apologies. Apparently Waitrose use them as well. A bit expensive, wife says look out for their offers. Hope this helps..
Pete