I dont know much of the history of mine, I know it came from Devon way when new and stayed in the general South West then up to Birmingham. I had run about 8 tanks of bio through it before I thought better of it!
Foolishly I did mine with about 3/4 of a tank - I could see plenty of crud in the bottom of the tank, got a lot out with magnet and hands - considering a flush out now.
To be honest I think its worth a check, I like Karls theory of it placing extra strain on the HP Diesel pump.
In my first picture above it looks better than it was, it was as good as blocked, Im surprised fuel got through!