Right, to replace, undo the top nut, also loosen gearbox mount. Place jack under engine and lift clear of front mount. Remove the 2 bolts from underneath the front beam. Then she slides off.
I replaced mine with a diesel front mount as its tougher than a standard Gti one. Again i would advise to replace all at the same time. Front: ?37 Gearbox: ?15 and back is about ?20