For £3,563 you should easily be able to get two J class flights on another carrier - perhaps Gulf Air?

I assume N class is non refundable, but really I reckon after your wedding you will be so knackered you would sleep most of the journey there even if you were on AAeroflot.

So I would on balance stick with Y.

You can buy some proper champagne on board, you get the lounges and showers at SIN anyway as you are a Gold, and best of all you have your lovely new wife to cuddle up to, which has to be better even than a flat bed!

Since you will have plenty of expenses anyway, and are budget conscious otherwise you would have booked in WT+ from the get-go, I would save the money the marginal improvement WT+ will bring, and splurge it on something special for your wide, a better hotel in Oz.

Remember you can upgrade with miles too....