New potential tenant

Guarantor

Hi there - We are private landlords who don't use an agency and use standard credit referencing checks for potential tenants and never really had a problem in this area.
Current potential tenants, one of them is on a fixed term contract for employment until March next year (contract will be for 12 months starting end October). The below is info provided by them in terms of previous experience they've had with this situation.....

"I thought Tom's family company acted as guarantor, but in fact it was Tom's dad (a Director) that was the guarantor, using company accounts as evidence of financial health. Looking at our correspondence from setting up the last tenancy, we filled out the guarantor form normally but instead of giving details of property ownership, we provided proof that Tom's dad is company director and submitted the company's last two accounts to demonstrate the health of the company. This has been the case in our last two properties. Attached are the accounts we sent last time (these are a bit old now, but we can provide up to date ones tomorrow)."

We would like a bit of advice around this. If we provide the credit referencing company their details, will they cover this sufficiently for us?
Or do we need to put details like this and the guarantor into the contract or separate document? If so, do you have examples?

We would appreciate a quick response as we'd like to let them know asap if we are going to proceed or not. We would like to but just haven't been in this situation before and want to make sure we minimise any risk.

Thanks
Lucy