Do you need to change the light fittings or change the 'bulbs'?
You know what, I've clean forgot where my LEDs came from, somewhere on eBay. You need to determine what type of bulbs you have now i.e. fitting and wattage and take advice on suitable replacements. IIRC ours where mr11 in spotlights and g4 in main light, then I added an extra spotlight over table and replaced spotlight over galley with a LED 'striplight'.
Thanks I will try and have a go tomorrow and take lights apart ...didn't think to look on ebay thought I would have to go to a specialist shop especially for motorhome parts.