>With regard to cleaning products used, the preferred weapon is Dettol anti-bacterial cleaner followed up with either Bob Martin Stain & Odour Remover or Johnson's ClearOff Animal Repellant and sundry room freshening sprays.
To be honest I've never found any of these to be much good

I've had best results with warm diluted BIO washing liquid, followed by spirit vinegar and left to dry
If the areas are upstairs maybe you could put up a stair gate to stop them having access? At least then you only have to 'patrol' downstairs which may be easier to manage?
If they were
cats I'd suggest putting aluminium foil in the places they offend as the noise of urine hitting the foil can put them off, don't know if it would work with dogs tho ??
Life is what happens while you're making other plans...