Cheers for the input guys, though the bike will use a BMX style freewheel I think not a freehub, so might possibly be cheaper to change the chainring and remove a couple of links from the chain, rather than buy new freewheel and new chain.
50/19 tends to be my “commute” gear on my road bike on 25’s at the moment, so I suppose equate that to 32’s and you’re probably looking at a 48/19, or using the original 16T freewheel roughly a 40/16. So I could just hunt out a 130BCD 39T ring on fleabay or something and that would do nicely.
Bike is only for riding in town by the way, furthest it will go will be about a 5 mile journey, with me wearing casual clothes and trainers on it, not kitted up in cycling gear or SPD’s.