Caution! I have an ongoing claim, started Oct 13 2023.
I'm using Safeguard (part of Swinton), and yes, Highway Insurance is also the underwriter. Good price c£325 with 2 years no claims and £100 excess.
LV have been completely hopeless. Firstly, they asked me for recommended campervan repairers(!!), then picked a local firm but omitted to mention they changed their mind and went for one 40 miles away. The repairer refused to pick up my Alphard (too far), so I called LV and they arranged it on Nov 10 2023, but far too early, as the spares have yet to get there, and are not due until 19 Jan. The repairer then helpfully told me the spares (the pop top roof in this case) are not standard Toyota (yes, it's a specialist van people!).
Certainly using a campervan broker you would expect some related knowledge by the underwriter during the claim process.
I'll be researching better underwriters.