No intervention needed: On Monday the 16th of February we spoke to a gentleman who had a vixen give birth to six cubs in his garden out in the open and he was concerned that they would be in danger if the vixen was to keep them there. The vixen may have been an inexperienced mother or one that was caught out and din't get back to an earth in time to give birth, so had them where she was at the time.

Whatever the reason we advised that they should be left for the time being as mum was laying with them in the hope that during the night she would move them to safety. On Tuesday 17th the delighted gentleman phoned to say all the cubs had been moved. Photo above is of a litter of cubs we had from Sheffield some years back.
med www.nfws.org.uk.