On receipt of the diary sheets participants will be randomized into an intervention or control group (see below). A therapist will explain the group allocation to the families at their home or their local CDC. The trial will run for 12 months with the outcome measures being taken by an assessor blinded to group allocation. The primary outcome measure (hip migration percentage) will be taken at 0 and 12 months so as to fit in with practice across the South West and not to increase x ray exposure. The secondary outcome measures will be taken at baseline, 6 and 12 months. The final RCT will involve a 3 yr follow-up phase.