Upperclass miles plus money LGW to Cancun

Have booked hotel in Mexico next year 7th June to June 17th. So now need to book flights when they become available. Any ideas the best time or chance of getting miles plus money for 2 people on this route. Would ideally like to do upper class again but would settle for premium economy.
Any help or info would be appreciated.

Personally would avoid MPM completely as you get more for your miles with upgrades from ECO 'M' fares to 'P' fare (PE reward) or 'G' fare (UC reward) - totally depends on how much you have to put towards your flight though.

Also to nab 'G' fares on a flight ex-LGW is a near miracle in itself so I would start looking as soon as the seats are released for purchase.

MPM I believe book into a non earning 'Z' fare for UC (will be corrected if wrong on that one) Again there are only 14 seats in the LGW UC cabin and they rarely go for a song.. MPM availability will be tight

Hope I haven't confused the issue further

Ideally looking to spend £1400 per person for the flight, less if possible. After flying upper at Christmas I really want to turn left again. Is it best to give flying club a call rather than book by internet as I must admit I do get slightly confused by it all. I have 19,000 miles and my partner has 13,00 so not that many miles.

You need 15,000 miles for an M+M UC fare (assuming any are available of course). Due to the split of your miles you would only be able to buy one (from your account) as you cannot mix miles from two separate accounts to get the 30,000 you need. Your wife could buy the 2,000 miles though.

To upgrade from an upgradeable PE fare to UV you need 12,500 miles per person per leg (so 50,000 in total)

But for a budget of £1,400 each that's going to be just enough for a cheap, non upgradeable PE fare (based on a dummy booking for November so June 2014 will be more than that) and an M+M fare in UC for that amount of money is an almost certain impossibility.