the only thing with that is I top up anyway at the start of every house when using the trolley, if you do get one can you review it, also you could ask Neal what components were used for delivery I,e if a shurflo pump and decent battery then the only thing to consider would be how robust the actual trolley is as constantly twisting and pulling over kerbs and different surfaces would soon warp something that's not upto it, Neal gets about a fair bit he may even demo one for you if he's passing by
Graham