Fleetscale do a plan and hull at 1/72 scale for HMS Cavalier (which is preserved at Chatham). Charity was one of the second batch of the c class and there were differences between the two. John Lambert plans also cover the first batch Ca class.
You would probably have to do some research but I expect it would be possible to use the Fleetscale hull and many of the fittings. Many of the ships were considerabley modified over their lifespans although Charity ended up in the Pakistan navy.
I have a 16 page brochure (A4 size) of HMS Cavalier when she was in drydocked in Tyneside. Brochure was issued by South Tyneside Metopolitan Borough Council.
If this is of any value please send a p.m. Not looking for payment, just p&p.