If your taps have a screw off/mesh bit at the end unscrew that and see whether you have additional nylon filters in there - we had that problem and it was cleared when I removed the little filters.
If your caravan is fitted with the Carver Cascade 2 hot water tank then a slow flow could be related to a defective non return valve which is a common problem with this particular tank. The ball valve inside the plastic housing starts to rust and over time affects the effectiveness of the water flow due to the fact that it doesn't open fully or fails to shut off. You need to look under the front offside seat and identify to see what tank is installed.