Thanks for the responses.

It's a little experiment at the moment, so I don't want to spend too much if at all possible.
Basically, as I've mentioned before, my girls all struggle with an antibiotic-resistant UTI, which they've had hanging around for nearly 2.5 years now
(mallethead). The reason I've resisted fleece up to now is because it can only be washed at 40 degrees, and I honestly can't afford to buy enough Vetbed to fill the cage and change frequently (ie only Petlife Vetbed can be washed at high temperatures - I've looked into this in detail before).
I am now thinking that keeping them extra dry might be a trade-off in benefits, so I just want to try it out. I'm thinking I will put Citricidal (grapefruit seed extract) in the washing machine to try to disinfect it, which I've done before.
I have just bought the Asda fleece throw, which I hope is going to be the right sort of fleece (100% polyester). Have measured it pre-shrinkage, and done the water test so I can monitor how well it improves and wicks after every wash. Am hoping 3 washes and dries will do the job...