I do have sympathy with the guide dog campaign as my wife is partially sighted. Their advice is cyclists should dismount on the footpath is perhaps common sense, but not compelling in the legal sense.
A footpath beside a road, or a footway, is a no no and must not be cycled upon, unless it is specifically designated as such.
Footpaths that are not alongside a road, such as those that criss cross many housing estates, are not covered by any laws that prevent cycling. Unless there is a local authority by law preventing it, then a rider commits no offence by cycling on these. A lot of people - and most reporters - don't know this, and many of the articles are written without basis in law or truth.