A quick search says Endsleigh can offer single trip business insurance at £100 and Columbus can offer annual at £20!
I assume the Columbus is for holiday only and not for business trips..
Any good providers of travel insurance for when I’m travelling as my Ltd co rather than an individual?

Ltd co makes no difference – if you have an annual policy now just add business cover.

Mines through first direct about £90 annual including most of the sports I do and business cover. Just have to top it up with something else for a week if I want to go scare myself in the Alps!

I have insurance as a contractor that covers professional indemnity, liability and tax investigation stuff, but it also has an option for travel. I’m with Caunce O’Hara and just checked and they quote an extra £74 for business travel and £116 for business travel & holiday. Not sure you can get it on its own through them though.

As said, personal travel insurances often allow addition of business. Though depends what they actually cover and what you want. The above insurance I mentioned covers business equipment taken on trips even if I don’t take the specific business travel insurance. Likewise personal travel insurances might have cover for some amount of business equipment. If you want liability cover while on business then that may need extra cover.