So you're buying Avios at 1p, which I wouldn't describe as cheap, just cheaper than other possibilities. If you have a very specific use for the 15,000 that values them at more than 1p then I'd say do it, otherwise keep the £150, it's a lot more flexible than an airline 'currency'. Have you maxed out Amex signup bonuses, referred partner etc. There's also this which may or may not be simpler than the balance transfer http://www.headforpoints.com/2017/09...deals-website/ there's a thread on Flyertalk about it too. Like all these things people have mixed experiences.