I've been filling out the paperwork recently, after my solicitor told me not to waste my money on getting them to do it, as it was pretty straightforward. She was right

The trickiest thing is getting the maps right and that's something they'd be relying on you to do anyway.
If they'd done it, it would have been about £150. If your croft isn't registered, you'll have to put in the registration paperwork at the same time and I think that's about a £90 fee to the Commission.