TenanCy agreement set up query

I have ask tenant to commit to 12 months tenancy with price rise half way through… He agreed to it.
How’s best to go about it. Is there a way to word AST like that? Or do I have to stick to 6 months tenancy and then renew Contract for another 6 months with a higher price?
It gives me option to set up contract for 12 months but I have to put the amount. I don’t think I’ll be legally able to ask for increase within that period if the amount ant the length of contract are in writing?

Why don’t you just set the rent you want from the beginning. You will only be able to increase the rent after 6 months if the tenant agrees it informally or if you have a 6 monthly tenancy agreement. That would allow you to serve a s13 notice as soon as the tenancy becomes periodic and the increased rent can then be paid from month 7, (or possibly month 8).

I never give fixed terms of more than 6 months anyway as in practice tenants will only stay as long as they need to regardless of the length of your tenancy.