Absolutely right and I did think of that. Join up (for free) or pay the first month for 5 and get approx 55 worth of service. (Bulb=25 to buy and 30 to fit)
I had a quick look earlier to see how easy it'd be to remove and re-fit.
It came out relatively easy but putting it back in was another story. Space is very tight and if the bulb starts to go in slightly off angle, the bulb catches in something. It got itself semi-stuck and I thought it was going to smash :-)
Reduced to using the tips of the fingers,
I might try a few times to get the hang of it.
Option of doing it oneself is, besides saving some cost, would be upgrading to something like a LED replacement but going BMWF makes a lot of sense. For a fiver :-)