My PTW gear change was also very tight directly after fitting. Fore-aft stick movement corresponds to rotation of the shaft in the selector, and is effected by the cable that acts on the selector tower by rotating it around its axis, not the one that acts on the bell crank through the white plastic slider to lift the selector up and down into the box. What I found worked with mine was releasing - and then almost immediately re-engaging - the spring-loaded plastic lock-ring without moving anything else (I was going to perform the cable reset manoeuvre but it started to rain as soon as I undid the cable-holders, so I abandoned the procedure without moving or setting anything (I had also not immobilised gearstick or the mechanism) and replaced the bonnet. Evidently the process resulted in that cable / cable grip relaxing by a fraction of a mm but that was sufficient to transform the gearbox from baulky into simply being quite mechanical - it has freed up considerably since with a year of use although I would say it is still a heavier but shorter shift than the 5-speed box (that is now in my other car, also full of new gear oil and a new slider). PTW was filled with new Comma gear oil before it was fitted. No other changes were made.