Rental income?

I have a new client, Ltd Co (hubby & wife) and have been informed by other folk that they have buy to let properties, several of them. when I mentioned in passing they said yes but as they don't do personal tax returns, they have NEVER declared them. One can of worms now opended!

As a sole practioner with AAT they act as my MLRO, I have asked but not had a reply as yet. Any suggestions?

Should I report on HMRC website? Or just request ITR for this year & sit tight????

PLease note their previous accountant has now been struck off ICAEW register !!!