”For everyone who's convinced we can dismiss because he doesn't have two years, he's a teacher, so we can't. They have continuous service under the national teacher pay and conditions regardless of how often they change employer (in the public sector).”
Sorry OP, but this is categorially not the case. You are confusing continuous service for the purposes of accrual of occupational benefits with continuous service for the purposes of accrual of statutory employment rights.
I’m not normally one to shout about my credentials but it seems to be particularly relevant, so as well as being an HR consultant I have just finished a five year spell as a director of a multi-academy trust. I am extremely familiar with all the ins and outs of the Burgundy Book and STPCD (more so than any teacher I’ve ever met) and have drafted teachers’ terms and conditions in discussion with the teaching unions.
If a teacher moves schools (or whatever setting you are) within the same local authority, they maintain continuous service for both statutory employment rights and service-related benefits as it’s the same employer. If a teacher moves due to a TUPE transfer, the same will apply.
If they move to a different local authority, or to an academy, that will not be continuous service for the accrual of statutory employment rights including protection against unfair dismissal.
If it’s a maintained setting, just in a different LA, their accrual of service for things like sick pay, maternity pay etc will be continuous.
If it’s an academy which recognises the Burgundy Book terms, it will be up to the academy whether they recognise previous service for these purposes. Some do, some don't, they are not obliged to. Or an academy might not operate Burgundy Book terms at all.
But for the accrual of employment rights, it needs to be the same employer or a TUPE. It’s simply not the case that once someone has qualified as a teacher, they are fully protected even if they hop about from employer to employer.