As with any insurance, it's just about reading the T&C's carefully - Animal Friends Petplan, NFU etc are just 'brands' for want of a better word, it's the underwriter or insurer that will set the T&C's, take your premium & ultimately pay claims. The underwriter will often change - not always, but they can do.
I personally haven't heard of RedSands who underwrite Animal Friends (I work in insurance). That's not to say they are bad, though.
I'm with AmTrust Equine myself & have been with Petplan previously.