I suspect that Kirsty wears the clothes she likes and feels comfortable in and sends the stylist packing. Why should her size or taste in clothes have any bearing on the programme, which is primarily meant to be about houses. She and Phil have a very good and witty rapport and they dispense a lot of very practical information about house buying in a pleasant manner that people will listen to and, hopefully, act on.
How many people not actually on the programme can thank Kirsty and Phil for their own successful house purchase?