Renewing uk passport in Colombia

Dear Sean,

Contact your consulate in Medellín, whose web page you can find by googling the phrase British consulate medellin.

The welcome page of that site specifically mentions passport renewals in the first paragraph.

cccmedia in Depto. de Nariño

I'm sure you have sorted this out by now, but there are no shortcuts, you can do it all online for a renewal, but you have to send your old passport back to the UK, the biggest cost for me, wasn't the passport, but paying for a Courier to send it back.
I'm not sure if I was just lucky but from the day I sent my passport back to the UK, to receiving my new one (they also send the old one back if it has your current Visa) was less than three weeks, which I didn't think was bad at all.

Can I ask who you used and how much it cost...looked up the website and thought their price included return... thank you

You're right the price includes the return leg, but not sending it over in the first place, for that I used Deprisa, who I think partner with DHL, I can't honestly remember the exact price, but it was about £50, which with the part paid towards having it returned doesn't make it a cheap option, I don't understand why they don't do them at the Embassy.