If i sit stationery and put the suspension to it's heighest setting it goes up fine,when i bring it down to normal position it comes down and you think its right down,but suddenly its like it has stuck at a a point then drops suddenly a couple of inches,then again!But does come down to the position i wanted,normal,anyone any ideas how to cure this,whats making it stick slightly at certain points?

Its probably the height control valve/s sticking. The linkage between the anti roll bar and the valve rusts. Give it a few squirts of WD40 over a few days and hopefully that will cure it.

Peter.N.