Hooray, the Amazon driver has just been and delivered my wiper arm puller tool. I dashed out to give it a whirl, removed the rubber cap and placed in the scuttle, undid the retention nut a few turns and slipped on the tool, (one thing to note is that it does not come with the required 8mm Allen key, so if anyone is ordering one, make sure you have a Allen key), gave it few turns, tool remained securely locked on with zero attempts to slip off. A few more turns and "Crack", the arm was free and yes the taper is indeed splined, moved the arm very slightly away from the A pillar and tightened up the nut nice and tight, went to replace the rubber cap, and its gone, can't find it anywhere 🙄. Oh well, tried out the wipers with a drenched screen and full speed and there was silence, no more smacking into the pillar, success, now to try and find another rubber cap.
One thing I did find though, was that the plastic under tray for the engine is missing, never noticed that before as I just thought it would be there. I can see the 2 side pieces that it attaches to and it looks like the clips etc are there so I'm guessing the dealer removed it when they did the engine and gearbox service and forgot to refit it. Anyone know the part number and the cost of it at all? I don't think it would be worth my while driving another 290 miles round trip to Mansfield to pick it up, assuming the dealer still has it?