A council client has started Path C scheme on non traditional PRC dwellings with predefined EWI measures. The assessment has identified cavity infill insulation in poor condition - a EWI systems installer has advised that it is fine to leave these in situ and install EWI over the top - however assessor thinks it should be extracted as it was installed some time ago so will have a different lifespan than the EWI and shouldn't have been installed in the first place to PRC construction type. What do we advise?