Increased both sides by an inch, so now 16" and 21" from 15 & 20. (GD1)
The drivers side could go longer but would there be extra strain on the motor?
16 is the max. on the passenger side, and 15" did not seen to be stocked.
£4 a pair at a cheap home & hardware shop so fitted with a 2 spares.
The rear is special case because of the plastic trim, but it's easy to just replace the rubber.
Take a standard blade, pull out the two stainless support rods with pliers from one end, remove rubber.
Do the same to your old rear blade, then trim the new rubber to length, insert, then slide original stainless supports back in - the last centimetre is a bit fiddly.
2002 car, have just replaced them for the 3rd time.
TG