Bridgestone Surface Cracks

Does this look right to you?

This is the front tyre on my Honda ST1100AY - that's the ABS version from 2000.  The bike had Bridgestone Battlax BT020 tyres on it when I bought it and I've kept to those tyres.  It must be on the 4th pair since I've owned the bike.  They do the job - a bit twitchy on white lines in the wet, but what isn't?  I got a bit of weave when I was riding too fast in the snow last winter, but I won't blame the tyres for that!  Except for the first pair,  I've bought the tyres from Essential Rubber as they're cheap and they seem to know what they're talking about.  They get lots of recommendations on London Biker forums, and they've been recommended by several of my colleagues who ride to work too.

But when the front tyre developed these cracks, I thought there must be something wrong.

It's only on one side of the tyre, but every single grove has a crack at the bottom of it.

So I took it back to Essential Rubber, and they had a look at it and said "Oh, Bridgestone surface cracks".  That's all it is.  Just surface cracks.  Won't get any worse they tell me.  Nothing to worry about.
I've had the tyre 10 months, and it's covered about 17,000 km, so it still owes me another 4-5,000 before I need a new one.  That'll be a few more weeks.  So if you see a white ST1100 chucked up the M11 one morning between now and the middle of November, you'll know never to trust when they tell you in the tyre shop - or Bridgestone tyres either.