Dog getting whiter

[Irishcobs]

My dog is now 7yrs old. When we got her, at a year old, she had a couple of little white patches on her, one on her neck and a 2 on her sides and a black patch on her tail, about 2 inchs from the base and about half an inch square.
Now these white patches had spread until she is almost half and half and the black patch had spread right down her tail till its about 3 inchs from the end. Is this just an old age thing, I have never known a dog have patches that spread like hers have.
Here are a couple of not so good pics so you get an idea.

 

[SSM]

Bumble Dog over the last year has gone a lot greyer - well she has been through it - however she is still as sprightly and mousing obsessed!! Also when she was a puppy she had no dark pigmentation on her tummy, now she has a splotchy tummy - too much sunbathing.