Rust options?

[deanobeano]

Gave the car a good clean and waking today

Whilst down at the bottom of the drivers door, I noticed a small rust bubble. On the sill and seems to be coming from inside out (ie paint is still intact).

What are my options with this? I'm unsure as to the BMW warranty on corrosion, the car is a 53plate, and will be 10 years old in November.

Pic attached.

Also, I noticed a small bubble (difficult to capture) on the boot lid. What would be the options for this?

Thanks