I too was planning a London trip today for football with an overnight hotel stay. I tend to buy Advanced Tickets & hotels as often a big saving, I can’t get a refund on the rail ticket or hotel.
The sad passing of The Queen aside I have several Advanced tickets booked (& a couple of hotel stays) right up to end of November but thinking in future it’s not wise to buy advanced what with engineering works & strikes (I know there are options on rail tickets to amend or get a refund re strikes)
EDIT: even though calling Southern Customer Services & being told I can change for a £10 fee it appears as ‘Travel with Confidence’ that is in place to 30th September I can in fact exchange for a voucher for use in the future, thanks to info from a rail colleague, shows what Southern CS know