new rent & new tenancy agreement

Tenancy Types and Management

I have agreed a new rent with my tenant, he has been in my cottage for a couple of years but the tenancy agreement had a restricted rent clause. Because I didn't need to I didn't increase the rent for a few years so when I did want to increase it I couldn't bring it up to market value. But now we've agreed a better rent I need a new tenancy agreement and am happy to let them have it for a year at this price.

My query is what is a good way to get a new tenancy agreement, since I don't need anyone to show people around, it is just a case of a new agrement. Also, he's offered the new rent from the next due date, which is the 14th april, do I have to get the new contract complete in time for this?

Can I use an online template agreement? My other property is fully managed & I've always used a let only agrement so I've never done this.