The original irmscher one on the nova sport, is the standard bracket turned upside down which lowers the alternator and cut diagonally in half and welded back up so the hinge is back on the correct side. Bit of bodge but uses original components which was a lot cheaper for irmscher. Bernie at Novatec in Slough, has made some brackets to lower the alternator down, there not spacer brackets but a completely new alternator bracket, which are better made out of steel so are specially made and not just modified brackets but he will charge you 40 or 50 quid plus vat for it. You will also need a new upper alternator bracket which you can get off any 1800 8v astra or cav, it needs to be longer as the alternator is now further away from the pivot, on the inlet manifold.
Hope this helps