If perchance the active runway is 18 or 36 it is most important to keep within the Redhill LFA and not stray into Gatwick's zone.
In practise it is easy and means the base leg (on 36) or crosswind leg (on 18) require a 100 degree turn to/from the runway heading and for you not to be more than a half mile south of the 36 threshold.
Believe me; I know how easy it is to do wrong if you don't pay enough attention !
The information on the aerodrome's website is most comprehensive and should be read carefully.
http://www.redhillaerodrome.com/imag...36_fw_v12a.pdf