Full suspension or hardtail for offroad in South Wales
Yes there are a few full suspensions in that range, they will be heavy, and mid to low level parts. Saving a bit longer and waiting (hard i know) Maybe £1200 - 1500 would get you much further.  

Your current bike is 17kg. a £1000 bike may only save you 1 - 2 kg. A nice hard tail within your budget would be very light (12 - 13kg)

Another option would be a 29er. the bigger wheels, and high volume tires will really help with overall comfort and capabilities on rocky technical trails, while still being fast and lighter than the full suspension in that range (but likely still 14 - 15kg)