Class rating test then you can sit an IMC test and they will add both onto your license at the same time. Although there maybe some worth to doing the full SPA-IR if done before EASA kicks in it will bullet proof you and won't cost much extra in the grand scope of things. Saves having to deal with IMC recommeded minimas and other such stuff. Once you have the SPA-IR they will issue a IMC on the back of a current one of them.
After having to do the IMC test myself after several years of multicrew LPC's its not a bad idea to revisit partial panel and the difference between RMI's and RBI's