... much as I would like to be able to help you, I am not, unfortunately, an "authority" on Visit Visas - aside from my awareness of how difficult they are to obtain (as I have twice indicated on your profile page) - so, in the circumstances, I'd respectfully suggest that, for the best possible outcome, you follow Terpe's guidance, #2 ... in conjuction with the sample template (mentioned in #4 & #7 and backed up by jta) provided by Mrs Smith.
Once again ... Goodluck!