Dave, give Ryan a call at Horizon on monday morning since if they could not see the problem but for you it still exists then it must be somthing that is within the car/equipment. To be fiar as helpful asthe forum is you will only probably get lots of "possible ideas"etc but Ryam should be able to give you some clear and straight advice..
As far as P and P making it as dear as a Novak, you have got a Loooonnnnggg way to go mate to catch that gap up, the Losi combo is £114.95, the Novaks are nearly £200
.......... (£85 in post, now thats a LOT of post
)