Major Class A airports will not accept anyone without an Instrument Rating whatever their licence as far as I know plus the cost of landing there will be eye watering
However you can if you choose land at a whole bunch of airports such as Bournemouth, Leeds, East Midlands, Bristol, Durham, Norwich, Liverpool, Humberside and others with a NPPL or PPL. If you plan ahead they will usually permit you to land although the aircraft may need to be transponder equipped and you may not necessarily get clearance straight away. Landing/handling fees however may well approach 3 figures so its best to avoid unless you really need to go there! Your ground school will cover the regulation of controlled airspace around commercial airports.
NPPLs can fly to Isle of Wight, Isle of Man, Northern Ireland. They can also fly to France and into some of Europe in a microlight if prior permission is sought. not sure about NPPL in a SSEA though. Safety regulations concerning flight over water will be covered in your ground school. Check out FAQs on NPPL website.
Generally speaking the UK NPPL will morph into a Euro Wide "Leisure Pilots Licence" over the next 5 years or so and things could change for the better or worse.
At Bagby North Yorkshire there is a 2010 factory built Microlight Eurostar available for hire at £57 ph wet.