It depends on each garage when they book people in for fitting. It also depends on your wheels. Balancing affects timing. A pair usually takes 30 to 60 minutes. With a four-wheel fit, be prepared for one to one and a half hours, so come before the scheduled time, if you can.
How long you have to wait for the mobile fitting also varies. It depends on the tyre type, your postcode and availability of the fitter for the day you selected. As you are looking, if mobile fitting is available for Chesham and/or the surrounding areas of Waterside, Chartridge or Asheridge, select mobile fitting at checkout.
If your selected tyres are in stock and if there are open local fittings, next day fittings are possible. After searching for local fittings, choose the soonest available time and date and try other nearby garages.
Look on the sidewall of your tyres or on your driver side door jamb sticker or look in your vehicle handbook to check for the recommended size (e.g. 205/55 R16). The Chiltern area has good all-season tyres for the rural driving and winter driving. Summer tyres are recommended for city and motorway driving. Consider fuel efficiency and wet grip to help you make a decision.