We recommend getting uniform from the Colchester Scout & Guide Shop located inside Mill Race Garden Centre, New Road, Aldham, CO6 3QT. This is open on Saturday Mornings from 09:00 to 12:00 except during school holidays; they carry all the uniform items you could need and have ones that can be tried on to check the fit.
If you are unable to get there then you can also order uniform online from the Scout Store or Amazon