By Jamie Spencer Manchester United risk going into the second half of the WSL season without sufficient depth at full-back if they don’t secure cover in the January transfer window. Rewind 12 months and it was centre-back that was a concern, with Millie Turner ruled out indefinitely at the start of the New Year. Veteran defender Diane Caldwell was drafted in and it proved vital because Aoife Mannion succumbed to an ACL injury only weeks later. Even then, both Hayley Ladd and Katie Zelem still had to fill in at the heart of defence at various points before the end of the season, removing them f…