As an update these coaches and their green companions have performed well 'in the wild' both here and at visited railways this year. The run of hot weather we are currently enjoying is the only reason for metal wheels to be fitted as the coaches ride well with the plastic ones fitted.
At 34 mm these wheels are larger than the LGB ones so it's Piko or Trainline 45 only. Having said that the Piko ones are solid metal bringing the weight up to 915 grams per coach.