Another option is Shanghai. The one way flight to MLE on Sri Lankan, with stopover in CMB is about the same as from SIN at around 500 GBP per person for business class (cheaper of course from BOM). No visa needed if your routing is LHR-PVG-CMB-MLE-LGW and your stay in Shanghai is less than 144 hours.
HKG also works (and would allow first on the 380 - but availability may be harden to pin down), with the HKG-CMB-MLE fare on Sri Lankan a bit higher at 540 GBP per person.