My friend messaged me before asking about their corsa's headlight.Said it's not as bright as the left side,tried changing bulbs but it's still the same.Had an issue with the indicator so had the relay changed,works fine when turning but said it looks like the orange light is stuck on.I haven't seen it,they only asked with me having a corsa just wanted to see if anyone had any ideas.

difficult to say without more info. Like is it when only on full beam or dipped headlight or sidelight. Unlikeley but could be the silvering on the back of the headlamp has corroded so not reflecting as well. This time of year the headlamp glass might need wiping but both usually the same muck on them. Damaged terminal. Might be they changed the wrong bulb? Does it have a separate parking bulb? Different headlampbulbs...one might be a brighter halogen bulb

Water ingress (usually in the rear light cluster) and bad earths.

Yes , I think gibbo is right , I too have had issues with my back lights, all not working at one point , hubby toke to Auto electrician between christmas /new year , had water problem and he sorted all the wiring out , now have a blown main beam , front , getting new bulb later , but I am wondering if it part of the other problem , I expect time will tell .Peaugot 307 .

On older cars (10 years plus) the rubber gasket seal between the rear light cluster and bodywork becomes brittle or hard and it stops deflecting water.

Get a piece of 5mm neoprene sheet from Ebay for a few quid and cut out a new seal.

Or head down to your local scrapyard and get one off a newer model car.

I wrote this detailed guide on water issues on my own Pug 307 a while back:

https://www.peugeotforums.com/forums/307-38/307-boot-leak-fix-208666/

Thanks gibbo , car not that old , all lights sorted now , it was blown bulbs in the front .