Polo eBay finds/marketplace

r/c - 32 ---- 33 ---- 34 ---- 35 ---- 36
19 - 44.8 - 46.5 - 47.8 - 49.1 - 50.5
20 - 42.7 - 44.0 - 45.4 - 46.7 - 48.1
21 - 40.6 - 41.9 - 43.2 - 44.6 - 45.6

A 33t would hardly be noticeable, almost the same as changing to 32c tyres, a 34 would be an ever so slightly bigger change than dropping a tooth at the freewheel, which isn't loads anyway, I'd look for a 34 or a new freewheel, whichever is cheaper/easier.

Very we'll proven, that's only 3% increase... But it may be just enough, and I think I'd need to add a link to my chain to get a 34t on (unless you've got one for sale - a convincing sales pitch)