I drive with my headlights on all the time, so go through bulbs faster than most. Anyway, the last bulb I purchased, from Nissan was $90 NZ, so guessing about 30 Quid. To get at the bulbs both panels around have to come off. I've not seen it done as Nissan have done for me both times I've replaced a bulb. Hope that helps a tiny bit.
ps. I'd stay with stock bulbs or you could end up with differing colour or brightness.