Well, hit the 40 nights now.

As said earlier:
2 x 10k points (£80-£100 value perhaps)
2 x 5 food & beverage rewards (5 or 10 x £15)
Suite upgrade(s) - already got 2 and the first expires next month.
Lounge access. Have to redeem within 90 days, so by mid-Dec?, so probably no use.

Doing 2 nights at present, one more on Friday. Friday may get me the first 4 nights for the 4 night elite credit promo that would take me nearer to 50 nights. Probably don't want another 5 x food credits for that.

Could possibly get another 20 nights this year at a push to hit 70 and take the lounge access then.