Two schedules with stated dates
The simplest structure is a base schedule that runs all year and an uplift schedule that overlays it between agreed dates. The uplift might add attendances, extend each visit, add a daytime amenity check or bring periodic work forward. Writing it as an overlay rather than a separate contract keeps the document manageable and makes it obvious what is additional, which matters when the invoice arrives.
Set the dates by observation rather than by the calendar. Many venues find their peak begins before the school holidays and tails off later than expected, and the transition weeks are often when standards slip most because nobody has decided which schedule applies. Naming specific start and end dates, with a review after the first season, converts a vague busy period into something both parties can plan staffing around.
