Personally I think the reason this is not getting much news is that the police don't need any help with it - they just need the evidence to prove what they believe has happened.
To make nationwide or even worldwide appeals for the general public to look out for her would result in their switchboards being overloaded with false sightings. Can you imagine the number of attention seekers this kind of appeal would encourage? They know she is still local, they probably have a very good idea of what has happened to her, they just need to find her or evidence enough to arrest and charge whoever the perpetrator might be.
BIB There's a huge amount of police activity at the grandmothers house according to Sky. It's been cordoned off with about 20 uniformed police arriving.