Hi can Anyone tell me if you can fit xenon bulbs as a straight swap from halogen bulbs? I got a feeling it's not that simple??

 

Xenon bulbs can just be blue tinted halogen bulbs that are a straight swap and fully legal
If you mean a hid kit then that is a little more complicated legally
They are also easy to fit but don't do it if you have h4 bulb or patterned lenses as the scatter will be horrific, also note that the current mot will fail aftermarket hid kits as they will fail the alignment check and I think they will be looking for headlamp washers and self levelling system. Although they are easy to swap back for halogen bulbs for mot. I had a set in a Subaru impreza think they where h7 single filament bulbs and they where very good but if you have reflector based lights get the ones with the shield on the bulb to reduce glare. Also don't go above 6000k as they will be to blue and the higher the number the less useable light they give out, 4300k is the brightest.