As I think was explained before...
(assuming a LH circuit)
Approach the field at 2000ft AGL keeping the field on your left. Fly turning left around the airfield boundary until you are over the numbers for the runway in use. Then descend deadside. (For RH circuit substitute right for left!)
This always works, and keeps you within the UK ANO rule that all turns inside the ATZ must be in the circuit direction.
Tim