It depends which aeroplanes you intend to fly in the future.
If your licence is for microlights only, the new EU regulations will have no effect, and you can continue to maintain and your use licence under the existing national rules.
There are very few non-EASA Self Launching Motor Gliders in the UK. Therefore, if you fly SLMGs it is likely that you will need to obtain an EASA licence before 8th April 2015. Under Part-FCL SLMGs with retractable propellers/engines are classified as “Powered Sailplanes”.
If you have an NPPL(SSEA) and you only ever intend to fly non-EASA aeroplanes (e.g. amateur-built), then you may continue to maintain and use your NPPL in accordance with current national rules. However, if you foresee a need to fly EASA aeroplanes (e.g. C172, Pa28) after 7th April 2015, you will need to obtain an EASA licence.
The conversion tables in Annex II to the EASA “Aircrew” licensing regulation do not include obtaining an EASA LAPL or PPL based on an NPPL. Separate provision is made in the regulations for the CAA to compile a report, to be agreed with EASA, which will define the conversion criteria. This report has been compiled and submitted to the Agency. The resulting conversion requirements are published in CAP 804.