I have a very poor hot water flow from the mixer tap in my kitchen. It is a Hansgrohe single lever mixer and all other taps work perfectly. I have replaced the cartridge in the tap with no improvement to the flow. I have disconnected the flexi hoses connected to the tap from the hot and cold supply pipes and swapped them over. This allowed hot water to flow as normal but very poor flow from the cold water. Could the problem be a blockage in the flexi hose and if so can this be easily replaced or could there be another cause to this problem.