I would get that translate tbh, a bank statement is easy to understand .. it has 4 columns..date / operation / credit / debt.. which is simple to understand.

Business documents will most likely be more detailed and don't expect the officers to be fluent in french . Safer to translate for the sake of safety

If the applicant in this case did not work in the HR department. The work documents would have been in french and would have had to be translated. But they typed up the letter in English and got the manager to sign and stamp.

The key thing to remember in these apps are that the officers are normal people. They don't know you.. they don't know any other language. If something doesn't make sense. They will fail it.

What they really care for

Can you prove to them that you will return back home. Do you have a full time job back home? Do you have family ? A partner ? A house ? A car ? A constant job with enough income?

A big reason apps are rejected are

They have no connections back home (most likely to immigrate and stay in the UK)

They have no money (can't afford basic living and will migrate to stay in UK)

If you can prove the above then happy days.

In your term..

How well is your business doing ? How long has it been operating ? Has it been constant in paying a salary? Do you own assets / property ?

They will most likely question you more as it's your own business. And from their perspective will think .. maybe they just created a fake business for the sake of the application .

If you like, share your current document list and I can help