What to do with tatty frogs?

[BFN]

Hello, I'm caught in a dilemma, horse is fairly new to BF, backs off mid July, fronts off mid August, at same time as in hand walking rehab started after collateral ligament damage.
In August farrier took a lot of thrushy frog off the backs, after 9 weeks box rest this was no surprise despite keeping bed as clean as possible (was on shredded cardboard, now on thick straw bed) since then he has been trimmed once again, back frogs were looking awful so trimmed and a bit off the fronts ( I was adamant not to touch the fronts) he also took a bit of sole off and consequently cob was a bit less comfortable for about 10 days.
At the moment horse is walking fairly well barefoot, heel first landing and better in front boots with 6mm pads (not comfy enough to trot sound barefoot though) but despite being as careful as possible with foot hygiene The back frogs are disintigrating & tatty and the bulbs of the front frogs are full of holes. We are up to 45 mins road work (walk) exercise now. Each night he is in & I've been cleaning in water or salt water & when dry slapping plenty of sudocreme in to all the cracks & crevices. So do I carry on & hope increased exercise sorts them out or is it time to get the farrier in again, I'm just worried he'll judge them to be in such a state & trim too much off so he'll be sore again!

 

[Moobucket]

I struggled to get my horses feet thrush free on straw, as its really isn't very absorbent and I'd find he was damp in the clefts of his foot.
I really rate the red horse products, namely the sole clense and the 'hoof stuff' (although its a nightmare to put on. Worked up a right sweat!). Formula 4 feet also seemed to make a big difference. Having come from the world of shoes I was used to seeing neat frogs, but actually dry healthy frogs are the goal. Now he is in proper barefoot work his frogs are tidying themselves up.

 

[BFN]

Thanks for your response Moobucket,
I'm keeping the straw bed really thick & am about to try a layer of either megazorb or hemp to soak up the wet. The cardboard worked well but I was using 4 bales a week at £7 a bale which was ridiculous, he was costing less to feed!
I started off with the sole cleanse when his shoes first came off but as the thrush took hold moved on to iodine, then the sudocrem. Tonight he looked lame in walk on the hard ground so I've texted my farrier & will get him out to advise me. This is all so disappointing, I'm doing this to keep him sound from navicular in the longer term but its heartbreaking to see him so fed up & sore despite my best efforts:-(