By the sounds of it, any fairly standard Personal Accident policy should do the job. As that Gruinard article says, they work by rating you on your “waiting period” at the start of a claim, then by how much you need cover for (weekly wage) and the cover type you want. It’s very dependent on your job too – office work is tons cheaper than scaffolder!
To be off work completely gets you full payment (temporary total disablement), some also do a partial payment if you’re able to do some paid work (temporary partial disability).
Personally don’t have any – just have 6-7 months net in the bank. Any decent insurer should have a policy for this often as a bolt-on to a household cover. Try NFU as I think they used to have one of these, not cheap though and you may be better off seeing what options an IFA can give you.