My Rottie has managed to slice a big chunk from one of her pads. I appreciate that I should be bandaging it, but we have just managed to heal a lick granuloma on that leg, (initially caused by too tight a bandage applied at the vets, when she had to have a toe removed). So I am between the devil, and the deep blue sea, as to what to do. The pad is cleaned regularly with diluted hi bi scrub, with an antibiotic cream applied, and she is on restricted exercise. Any other suggestions gratefully received.

A twice daily soak in lukewarm slightly salty water will help it heal.  Otherwise you're doing everything right - even bandaging doesn't help after a little while as you want airflow to get in and help it heal.   The biggest issue is dirt getting in - not so much of an issue indoors but you could tape a sock over her foot while she's outside to keep the worst of it out, and it can come of again inside.  Or a boot would do the same thing, if she'll tolerate one.  Once the hole starts to heal up she should be fine.

my old weimaraner did similar- very deep cut full length of pad. I did it in salt water twice a day and when she needed to go out to toilet put a plastic sandwich bag on her foot- held on with a bit of tape.  When I started exercising her again I got her a dog boot and a few pairs of childrens socks- so clean sock over wound- boot over top and wash each sock after use so as inside o boot didn't turn into nasty mess. 
She heeled very well and I think did better allowing air at it while she was indoors

My dog had a cut on pad. We had a plastic sock to pop on when we took him for road walks only for a week. Vets checked it three times. We soaked his foot for a few days in salt water once we stopped using the sock.
We used a protective halo to stop him trying to nibble it.
It went from pink to dry quickly and no infection

My dogs often get cut pads due to litter (broken glass mostly) left by tourists/fishermen at the lochside so I always keep the following in the medicine chest: low adherent dressing, sudocrem and cohesive bandages. I also save any plastic wrappings from dog treats/chews packs as these are quite robust and fit well over a paw and so are good as a cover when walking. So I put sudocrem on the cut, low adherent dressing next then wrap up with the cohesive bandage. If you have ever put a tail bandage on a horse use the same technique, if not then do this: start with end of the cohesive bandage at front joint (ankle or elbow depending on leg) then loop up to other side, fold down and then wrap around leg down to pad and back up again as quick as you can. Cohesive bandage is great but you kind of need to do it in a oner, otherwise you just get into a holy mess of sticky bandage! Especially if you are trying to bandage a Flat Coat.....flat coat owners will know what I mean.....:-) Lick lick lickety lick from my girl, AKA Little Miss Lixalot

I would salt water soak and just keep on top of keeping it clean, whenever mine do this I only wrap it if it's bleeding or if they're going outside. Colloidal silver is also absolutely brilliant for feet.

One tip I picked up along the way.... lurcher people swear by feeding black pudding for cut/scuffed pads.

Realise that slicing a section of pad away is different from a cut but was given the suggestion by a couple who race huskies locally, that for cuts to pads they always use haemorrhoid ointment to help keep it closed.

Haha to bandaging a licky flat coat or bandaging a gsd with a licky fcr present.i be been doing just that to a foot for the past few weeks

Gosh the many uses of  haemorrhoids cream .it waa supposed to be good for bags under the eyes now who found that out !

Best thing I was told to keep foot dry outside was by a Vet. He gave me a blood/drip bag which is strong and the holes at the top can have a lace or similar threaded through to get a nice tight fit on the leg. I always found normal bags wore out or fell off part way through a walk.

Thank you everyone for all of your advice. The pad just refused to heal, and appeared to be looking slimy, so as my girlie has been prone to wet excema in the past, (which only heals with antibiotics), she is now on a course of antibiotics, and the pad is now showing signs of healing.