Autotrail 610 SE

Hello we bought a Auto trail 610 SE 18 plate about 13 weeks ago and after it had been on the drive for a hour we had water coming from the fresh water tank ,it seems that the inspection cap had been cross threaded so not a good start, I filled the water tank up on Thursday just gone 16/8 so we could have our first trip away , We got to the pub stop and did not use any water until Sat 18/8 and then only for washing and making coffee ,I noticed that the water tank bars were only on 2 instead of 5 ,so we then moved to a different pub stop and in the afternoon the landlord let us fill up with water but has soon as it filled up it began to pour out from what i thought was the overflow pipes and the bars went back down to 2 and the red light came on so something was not right as I said this 610 SE is only 13 weeks old is there something i have missed because this cannot be right , Has anybody else had water issues thanks Neil.