Remind past customers it's time to book again

Help me remind past customers when it's time to book again.

My business: [what you do]
Services that repeat and how often: [e.g. boiler service yearly, gutter clean every autumn, haircut every 6 weeks]
How I contact customers: [text, email, WhatsApp]
How I track due dates now: [e.g. not at all, diary, spreadsheet]
Any reason to book early: [e.g. autumn gets busy]

Ask me up to 2 short questions first. Wait for my answers.

Then:
1. A reminder message for each service, under 50 words, with an easy way to book.
2. A follow-up for people who don't reply.
3. A seasonal message for times of year when everyone needs it at once.
4. A simple tracker: customer, service, last done, next due, reminder sent.

Helpful, not pushy, UK English. Add a simple opt-out line to each marketing message (e.g. "Reply STOP if you'd rather not hear from me"), and remind me to message only past customers who haven't opted out; I'll check the ICO's guidance on marketing texts and emails.

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