Hi,
The first thing to point out if your not used to caravanning, then your expectations may bigger than the system is able to provide. Domestic water systems may see water pressure of up to 6Bar, but caravans have to be limited to no more than about 1.5Bar, and whilst domestic pipework uses 15mm thin wall pipe with an internal diameter of about 12.5mm, caravan pipes internal diameter is only 8 to 10mm.
At best you might get a maximum flow rate at a tap in a caravan of about 4L per meanwhile at home you could get 8 to 10 /min
But there are other factors which might also affect the delivery in a caravan whilst using a direct to mains hose system.
Obviously if the flow and pressure at the mains tap to which you connect is inadequate then it will affect the flow in the caravan. Also don't forget if there are several caravan pitches all using water that may also affect your tap.
The hose system uses a special pressure reducing valve. Ultimately to reduce the pressure it has to add some restriction, and that could affect the flow rate into the caravan, and it might not be able to match the performance of the water pump.
One solution might be to use the caravans water pump and an external barrel of water, just like not having mains water, but to have the barrel fitted with float valve and to use that with a hose pipe which keeps the barrel topped up. These are available...
This is an example
This way you get the convenience of mains water, but you are also protected from any weakness of flow or pressure from the sites system.