Franke "Eiger" mixer tap - leaking cold side; obtained new (expensive) valve, then the fun started. Wouldn't budge when I'd removed screw./ Soft water area but tried the dilute acid and then the "tapping" - more whacking with a wooden implement. Finally protecting surface - mole wrench and brute force. No joy. now have separation of around 2-3 mm and no further progress. Any thoughts on what next. Removing whole tap to work on is going to be b....y difficult. beginning to think Franke goods are more of a liability than a blessing.