Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.601 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)

"At the moment it's just not feasible to drop £1.5-2k on a business ticket when I'm okay in economy."

When airlines like AA and US run sales on their frequent flyer miles, it's often possible to buy these miles for about $.02 USD each. If you can find award space on one of their partner carriers (like CX), you might find that you can get a Business Class roundtrip for a reasonable price. You'd need to avoid flying on BA metal because of high surcharges. And if you can depart from somewhere other than the UK, you will avoid the high UK APD, even if you get an "open jaw" award ticket, and return to the UK. (Using BA Avios for a cheap, one-way Reward Flight Saver "positioning" flight to AMS or BRU can be very useful in this regard.)