Hi everyone, just to let you know i bought the oven thermometer and it turns out what i thought was 160 was actually 180! so that explains why my cakes werent rising so much and also why the middles were rising loads and cracking but were raw and doughy.
I twiddled with the oven until it was 160 and got perfect flat well risen (like almost an inch over the tin) cakes which cooked evenly. no more crispy tops with big mad pointed middles and raw insides. no more wasting half my cakes after leveling.
Cant believe this was what the problem was, i totally trusted my oven, obviously now its getting used so much its messed up a wee bit but thank goodness its fixed, it was literally on the verge of cracking up.
thanks for the advice!