The Access Code says:
Access rights are exercisable above the surface of the land and so extend to non-motorised air sports, such as paragliding. By their very nature, many of these activities require the use of hilltops and escarpments.
Maintain good liaison with relevant land managers at well-used launching and landing points. Take care not to alarm wildlife or farm animals and avoid damaging crops. If you wish to set up a landing point, such as for an event, contact the relevant land manager(s).
If you are kite surfing, follow any local advice about wildlife and minimise disturbance to birds and animals.