Don't have a hue amount of sympathy about the "Loan Charge". This is where people were paid in Employee Benefit Trust Loans because loans weren't taxable. The standard thing was to be paid 7K in salary and take the rest of the money as tax free loans. HMRC started chasing this about 6-7 years ago and changed the law to bring all EBT loans from 2000 to the present into scope for taxation as salary.
This differs from being a PLC contractor because we actually do pay tax (corporation tax, VAT, employers NI, employees NI personal tax, dividend tax, etc).
There is an "opportunity" to settle and pay HMRC what is owed and be indemnified against future investigations on EBT loans. If you do this you can negotiate payment terms and pay them over a number of years.
I've done both. I have a moderately sized loan charge I have to pay but I've settled with HMRC. I did the EBT thing for about a year when I started contracting because it seemed easy and my head was turned by the money. I dumped it when I started my second contract because I had realised that, if something seems too good to be true it probably is.
When HMRC contacted me about the EBT thing I immediately started putting cash aside for this because, as they say, the only certainties are death and taxes. If HMRC wanted the money, they were going to get it.