These look similar to what came with my tie bar lowering brackets. I presume the distance between the bolt holes on those spacers are equal to that between the bolt holes on the suspension arm, albeit of a slightly smaller hole diameter? If so, then they look as near to perfect as I will get. The only thing you don't mention is where you got them; and if they're not an off the shelf item, did you have them made? If you have the dimensions of the spacers, i.e., height, width, length, that would be very helpful, as I will just order some aluminium blocks at the correct size and drill the holes accordingly to fit the bottom of the arms.
*Edit: are these the above spacers you used?
http://www.lmfvauxhall.co.uk/Anti-Ro...-Kit-Nova.html; or these ones:
http://www.ebay.co.uk/itm/Anti-roll-...p2054897.l4275