There are three things that can cause bulbs to fail, the first is over voltage but that would affect all of them, the second excessive vibration and the third poor quality bulbs. Have you actually tested the bulbs you removed? The problem could be a poor connection on the lampholder.

Have not checked the blown bulbs but will in future. Will also check the connections although connections appear good and the aperture cover to the bulb holder area is tight. It just seems strange and it is not the first time it has happened. Have purchased all bulbs from Halfords. Are there any other bulb type or makes that I should try? Thanks for your advice.

I normally have the light switch turned to automatic. Had the same issue with lamps on my previous Peugeot 407.

Presuming this means headlamps are on all the time the car is in use, they might last longer if only turned on when you needed them. Or is that a strange old fashioned idea?

No, it should mean that they come on automatically when the light sensor detects a low enough light level to warrant headlamps being on.

However, this does mean that the headlamps will often come on briefly while passing under bridges, low-hanging trees and such. Such repeated on/off cycling could well be contributing to shortened bulb life. Halogen bulbs don't like that treatment as they only do their "secret sauce" bit of depositing vapourised tungsten on the thinner bits of the filament (hot spots) when good 'n warm.