Here is the link for a free chess tactics server:
ChessTempo
I believe this gives a very realistic assessment of tactical ability.
This will be useful for Junior Players ...
Also, for the Seniors I recommend signing up to:
International Chess School: (A little pricey – approx £25 per month) but, you get openings / strategy and tactics problems.
(Supposedly prepared by a Grandmaster)
Chess Masters School
Active Rook vs passive Rook
12 years ago