Booked up 3 months in advance? How many do you do a day? Surely redos will not wait 3 months I wouldn't.I started 12 years ago, highest price in the market place and have never discounted my price.
Once you discount a price it is extremely difficult to reset to your normal price; instead use an added value mechanic, for instance a Half Price Extractor clean with every oven cleaned during November, then full price for December, and straight in with a £5 Hob clean with every oven cleaned in January.
Mix and match, interspersed with a month or two without promotions to build a profitable business initially. I haven’t given any promotions for the past 8 years and I’m always fully booked at least three months in advance.