I know Hastings do.
Their claims phone number takes you straight to 4th Dimension
the Hastings policy booklet offers two options:
"Can I choose my own repairer/garage?
Yes you can take your motorcycle to a repairer of your choice but if
you do so you won’t be entitled to the benefits available under the
nominated repairer scheme.
You will also need to submit a repair estimate to your insurer for
authorisation before the work can start, which may delay the
progress of your claim and the repairs to your motorcycle."
What are the features of using the nominated
repairer service?
Repairs The repairs will be guaranteed for five years.
Authorisation You don’t need to get any estimates so the
repairs can begin as soon as your insurer has
authorised them.
Delivery The repairer can arrange to collect and return
your motorcycle.
Payment All you need to do is pay your agreed excess to
before the motorcycle is delivered back to you.
They do not specifically name 4th D as the nominated repairer, just a vague definition of using an authorised repairer.
I guess it all comes down to how much a claimant wants or is capable of being their own project manager. If you want to use your own repairer you will need to get the bike to them, which might be fine in a minor spill where you are not injured. If you are carted off to hospital then the bike will end up in a police compound racking up storage fees.