The distance from the water level in the tank to the top of the tallest
radiator is approx 1 metre.

Provided you managed to bleed the rads until water came out, you are fine,
although limited head can cause other problems, like pumping over, in some
situations. It is possible that your system needs balancing. If other rads
are stealing all the hot water, some rads may not got hot all the way up.

Christian.