In addition, as is usual in, for example, the aircraft chartering market, the nature of the services must be such that a reasonable supplier would not be able to guarantee its offer for 10 days.
At hynny, fel sy'n arferol, er enghraifft, yn y farchnad hurio awyrennau, rhaid bod natur y gwasanaethau sydd i'w cyflenwi yn golygu na allai cyflenwr rhesymol warantu ei gynnig am 10 diwrnod.