David and I both fitted the proper curved blade some months ago - miles better than any other blade I've tried. He'll agree, I'm sure

Overall 21.5". But a 23" blade still works for me. ;)

I don't doubt that for a moment, but I'm fascinated now why that should be. I mean, I can think of a few advantages of having a curved blade, but I can't think why it would be that the curvature alone would make it wipe better than a straight blade, except maybe if by being curved, the increased vertical distance between the middle of the blade (ie the peak of the curve) and the ends of the blade, create a more rigid structure, one that is less prone to wobble/judder as it moves across the windscreen.

Other than that, I would imagine the curvature would have the cosmetic advantage of bringing the tip of the n/s wiper closer to, and more inline with, the bottom edge of the windscreen. No doubt the curve also reduces the overall effective straight-line length of the blade, but if that were the only advantage, a shorter straight blade would be just as good.

I think the D3 blades are Valeo as the rubbers say SWF on them - but most other VAG cars are BOSCH Aero but there is no Valeo aftermarket part number for UK/RHD and places that sell these are selling LHD parts, but the EKTA specifies different part number of RHD & LHD and different for passenger and driver side but aftermarket ones are usually same for driver and passenger so there must be some compromise.
https://www.youtube.com/watch?v=F8kHXwEzCw8
https://www.youtube.com/watch?v=XhNDZOd9G9U

Don't confuse Valeo with SWF.
SWF is premium german brand for wipers. SWF is better than Bosch.
Valeo is cheap s**** in comparison.

That logic was true for D2. SWF may be owned by valeo, but the quality and brand are separate.

I had to replace my blades recently, I read this thread and was going to order SWF from Germany, but in the end I just got Bosch blades from Halfords, they seem to be good quality.

I had non genuine blades when i first bought my 8, switched them out for genuine and was much better, and now i can change the rubbers too, TPS 7.50 i think it was. Quantum blades also available too and are really reasonable.

Just a question, how often do you guys clean your blades? I was getting smearing and cleaned the blades with meths. Apparently they don't need changing as often as i thought.

I don't clean them. I change to genuine SWF rubbers on my D2 every year which I buy from TPS.

I need to order new wipers for the D3.
wheres the recommended place?

I'd use TPS. Even the cheap Quantum blades are ok and only a few quid each