Should I stay with my full suspension mountain bike or buy a hard tail?

Summer is coming up and I don't know weather to keep my full suspension kona king kikapu it's only 100mm traval anyway or buy a on one inbred frame. I have 100mm fox 32 forks and use it in my local wood sherwood pines which Is quite flat and sandy perfect hard tail terrain but I also ride up at Wales and the lake district which is hilly and rocky !... I ride xc but a little light downhill :-) at the pines :-). Thanks for reading what do you think ??