Yes, from LASORS 2004:
Under the ANO the designation ‘Single Engine Aeroplane’ (SEP) includes all microlight aeroplanes and SLMGs. Accordingly, the holder of a UK JAR-FCL licence with SEP rating may, subject to appropriate differences training, exercise the privileges of their licence on microlight aeroplanes and SLMGs in UK airspace only, without the necessity of obtaining a NPPL which would be the normal licence of issue for such aeroplanes. However, any experience gained in microlight aeroplanes or SLMGs cannot be counted towards the flying experience necessary to maintain the full SEP privileges of the JAR-FCL licence.
Thanks for the heads up Stan Evil!