hmm, mine does funny things like when i dip the clutch in 2nd to change down at a roundabout, it dies, then if im quick and lift the clutch up fast, it kicks in again!!! strange!, never had the problem you describe though. coolant leak? and is the fan working? my temp gauge never goes over the half way mark ( apart from last weekend but we dont talk about that)!. :-kyou could try googling daihatsu drivers uk, they may be able to help.
ben