Issuing notice to quit, wording?

[MogadoredMemoo]

Can anyone please advise me as to the correct section (21?) for no fault notice to quit and how it should be worded? I'm getting myself in a mucking fuddle!

[lalalonglegs]

Does it have to be really formal? Are your tenants likely to ignore it on some technicality if it isn't? I always just write something along the lines of: "As you are aware, your lease on xxx property comes to an end on xx date. This letter gives you formal notice that the tenancy agreement will not be renewed after that date and you will need to vacate the property before or on that date. Yours sincerely..."

I have only given notice to quit twice as we are usually happy to roll over contracts and I always gave the tenants plenty of notice but just dropped that round too as belt and braces measure.