50hz pulley
First off, congrats on finding your dream set! Unless John has a secret stash of 50hz pulleys on hand, finding one from a distributor can be tricky. Here's a note I sent to another member last year regarding the pulleys -
Unfortunately it looks like the 50hz pulley is no longer available from most sources. The last PN I see available was the Y202496, but 202496, 1245651, 2-2496, were also listed at one time. The 50hz pulleys are a heavy machined pulley, rather than a stamped pulley that I've seen on may 60hz versions. You may want to keep a search active on ebay, just in case. The belts appear to still be available from a few sources.
To be honest, I'd clean the washer up, install a new injector, rebuild the motor glide with a new kit, clean the pulleys, install a new drive belt (pump belt should be fine), replace the water valve if you are concerned with using the original, and run with it. Several members have had no issues with the wash action of the A806, as they came from the factory. Personally I feel the A806 was the best of the best and I wouldn't change a thing with the drive system and leave it the way Newton intended it to be.
Ben