Is it worth it (LDN - SYD) Business Class?

Hi all
We are flying home from London to Sydney for our wedding in a couple of months. Currently booked for PE (which we paid GBP2.5k each). Looking to upgrade to business but will have to pay cash as not enough points to upgrade both / not enough rewards seats left anyway. Got quoted GBP4k to upgrade just the 1st leg (LDN - SYD), but GBP5k each to upgrade round trip - so even though the first leg is the main one we care about (since we are brining wedding dress / suit back with us etc) it would make sense to do both legs. Question is, is it worth paying the extra GBP5k to upgrade?

Flew Singapore PE about 2 years ago and it was really nice, definitely better than normal econ. Business seems an even nicer step up, and given it's the wedding and all, we are ok with doing a bit of a splurge for this occasion - particularly if it would mean the airline staff would take a bit better care of hanging up dress/suit on the plane, etc. But is nearly 3x the PE price a 'splurge' or just ridiculous? Idk so thoughts welcome particularly for those who've flown recently

TIA!