Briefly, client fairly new to me; filed own returns for years, brother of longstanding client, came to me due to HMRC enquiry.
I sorted enquiry without tax or penalties due, but it emerged he'd been completing self-employed pages to disclose his rental income.
I also completed his 2014 return.
He promised to let me have 2015 info on a couple of occasions, most recently two weeks ago; just looked on HMRC list and see he's filed it himself. However, guess what, he's used the Self-employed pages again! The amount he's been charged for Class 4 NIC is considerably more than I'd have charged him for the work.
So, to my header - what would you do?