The advice from Mark at WF was to remove the wiper motor, strip down the gearbox and move the park detent to the alternative position. First step was to remove the wiper motor which required the dash and ECU panel released for access, then the nearest wiper drive unit cover removing to release the drive tube, the 2 x mounting bolts and connector removed. The motor could then be removed from the scuttle carefully extracting the drive cable.
With the motor out the 4 x bolts that hold on the gearbox cover were removed and the gears accessed. The drive cable and link arm were released by removing a circlip and then the motor turned over and the circlip holding in the holding in the main gear removed. The main gear was then pushed out and the white plastic detent pulled off and refitted into the alternative position, 180 degs from the original. Everything was then put back together and the wiper motor refitted - the reverse of the removal. Unfortunately no photos because by this stage I was covered in grease.
After a quick check that all now worked I fitted the wiper arms and found the next problem - the wiper arms jammed up against the windscreen and blew another fuse. I did the best I could to fettle the arms and drives to achieve a better angle and eventually got everything working - hopefully well enough for the IVA. After a quick check of low and high wipe I ran into another problem - the wipers wouldn't switch off. After checking all the switches and connectors were connected I remove the motor again and discovered than the circlip that holds in the main gear was not fitted correctly allowing the gear to ride over the detent. I refitted the circlip (removing knuckle skin in the process) - tested all now worked - it did - and then fitted the wiper motor for the third time. I wired up the heated windscreen while I had plenty of access then called it a night and went inside to apply plasters to knuckles and order some fuses!
2 hours thus bring the total build time to a double century - 200 hrs