Extra bottle cage for extra fluids.
Riding around SE London is probably not going to be much real help, the hills aren't really long enough and I'm not sure getting buzzed by the 356 / 354 is going to help you out in Spain.
The long game is definitely the one to play here. You've got six months, or 24 weeks if you prefer. Which probably gives you 72 sessions of "training" to do what dbr suggests. Long, slow, steady, is going to get you up the climb so you can enjoy it. A bit of strength work is always good too.
Extra bottle cage for extra fluids.
Riding around SE London is probably not going to be much real help, the hills aren't really long enough and I'm not sure getting buzzed by the 356 / 354 is going to help you out in Spain.
The long game is definitely the one to play here. You've got six months, or 24 weeks if you prefer. Which probably gives you 72 sessions of "training" to do what dbr suggests. Long, slow, steady, is going to get you up the climb so you can enjoy it. A bit of strength work is always good too.
It's totally doable.