I found those fabric belts Vaughan. They're from HGW, a Czech company, and available in Luftwaffe, USAAF/US Navy and RAF, in 1/48th and 1/32nd scales.
Hannant's have the 1/32nd scale FW 190 set at £6.60, for a set of two, micro-fibre fabric harnesses, plus etched metal buckles etc.
The pic below shows the 1/48th scale USAAF belts.