Is the Mk1 Octy supposed to have two different front wipers?

My passenger side one is shorter and curved whereas the drivers side is long and straight (Aero wiper). Are they supposed to be like that or has someone put the wrong wipers on before I had it?

That's correct

yes that is correct and after market ones don't have the curve in it.

last time I bought some from the dealer it was cheaper than buying a set from halfords!

Yup, that's right. Also found dealer cheaper than aftermarket.

Yup same as Mk4 Golf, only place you can get for post 2001 is from Dealer.

Halfrauds only have pre 2001 and the passenger side has a straight edge so is useless - plus cheaper at dealer

It's a common part number to VW, 1J0998003 is a pair of front wiper blades, remember to reverse the clip positions as they are set up for left hand drive out of the box, otherwise you'll put them on upside down,