Is there a replacement LP which has a pump and the filter / water seperator on the tank side of the pump ( suction side )?

 

You can add a Racor fuel filter/water separator to the suction side of the LP of your choice(Walbro seems to be the best value for money in LPs). Suction side filters are coarser than normal filters to reduce restriction, you will be fine with a 30micron filter.