Rob I heard RTA instructed all registered engineering firms which certify for the RTA that they arent allowed to restrict/modify and re-register any motorbikes from a different CC for LAMS approval. So make sure you can do it by calling up some approved workshops (see RTA website for list) before you buy it.

Happened after RR motorcycles was selling CBR600/GSXR600's and getting them detuned and re-engineered. They never originally had approval from the RTA to do this (regardless of what he says) and all the poor pricks that bought these bikes off him had the RTA de-register and re-register their bikes without LAM approval.