Most airlines will not let you fly from the UK unless you have a return or onward ticket, as it is they get a massive fine. Singapore Air asked me for a ticket at Heathrow. Just got 30 days at the airport and in that time made the arrangements for the wedding. After 28 days went to immigration office and extended to 59 days and in that time got married. Then went to immigration again to apply for 13A visa to become permanant resident.