You could try re-pitching the yeast.
Another way is to remove 2 litres of your stuck wort, add 1/2 litre of water and re-pitch.
When the ferment fires up, keep adding the rest of the wort a couple of litres at a time.
It doesn't seem to make a deal of difference which ever yeast I use, they all come out at 1004 - 1006.
So your 1008 seems quite reasonable to me.
And yes, my hydrometer does read 1000 in water at 20C!