If you can build your own, you can get Miche track hubs for under £60 a pair, and you can fairly easily get perfectly decent rims for about £30 a pair and spokes for £20, leaving you £90 out of the arbitrary £200 for a lovely Eno freewheel, which IMHO is almost an essential item.
Or you could go for a Halo or Surly rear hub and a £10 Shimano front for about £10-20 more.
There’s not much to go wrong with singlespeed hubs, they’re just four bearings, so there’s not much to get excited by on the expensive ones.
the Gipiemme Roccia wheelset for £70 is fine
Except that for a singlespeed with rim brakes and a 120mm back end it’s completely useless 😉