I've just done a complete rear brake overhaul on mine this last weekend, detail
here.
The shoe linings looked fine and there was little or no corrosion in the handrake area other than on the actual drum away from the shoe swept area. However, I will check how well bonded the linings on the shoes still are by using a screwdriver to see how readily or otherwise the lining can be debonded.
Several years ago, I had one of the last Vauxhall Cavaliers before they became Vectra's. At around 70000 miles or so (4 years old), one of the front pad linings delaminated without warning. No damage but it was a strange experience when suddenly the brake pedal went nearly to the floor. My own check at the roadside quickly identified the problem but there was no time to source & purchase parts as I would normally have done. I just took it into the nearest QuikFit type Tyre/Brake centre for a full front disc/pad change. The pads were not excessively worn either.