Fantastic to see this finally confirmed! On my recent visit to LGW, I was in South terminal very briefly and it was awful seeing it deserted and devoid of life compared to when I last flew out from there with CX to HKG in February 2020
So it'll be good seeing it come to life again later next month!
The terminal page at LGW has also been updated with all South-based airlines moving back, but is missing Scoot; are they likely to be remaining in the North terminal or move South when BKK/SIN recommences?