Is there merit in an applicant for a spousal visa to attach

[junosword]

Is there merit in an applicant for a spousal visa to attach

... a covering letter in addition to the application form and sponsors letter?

If so, what should be included.

Many thanks

[Sammie]

Hmm, maybe the applicant could put in writing their intentions once they arrive in the U.K. You could say what you want to do once you arrive in the U.K. Give details of a job offer or types of work you will be seeking. Maybe state that you intend to take up English classes (if from a non-English speaking country).
…Perhaps something along those lines?

[parvez]

My wife submitted a covering letter with her application form and letter from me as sponsor.

It should include a statement to say that the applicant is married/engaged to the sponsor and intends to live with them on a permanent basis.

It should also include details or clarifications for anything in your case which you feel requires it. Use it as an opportunity to give details of anything that isn't already covered by the application form and supporting evidence that you submit.

[junosword]

thanks for your responses. The advice is much appreciated.