My partner has just gone to DHL in Stratford and they won't accept a box (containing chinese paintings) as it's too large. An aunt has just died and this is hers with the house being cleared out today and tomorrow.
It's 90 x 43 x 13.
I'm looking at ba and their allowance seems to be okay at 90 x 75 x 43.

I don't want any hiccups at LCY so am simply asking what could go wrong? It's an Economy flight on Sunday LCY - BHD and already has one suitcase so should be fine to add another.