I got my wife's 10 year standard visitor visa in 2023 for £860. Approved with no issues exempt the wait was longer than expected due to the flood of Ukranian appliications being processed.
I found it easy to do myself by going through the online application and making careful note of every requirement in every section then putting together an application letter ensuring that every requirement was included and had references to attached appendices which contained the documentation which addressed the requirements.
The tourism extension is 30 days. The "visit Thai family" extension is 60 days but some up country Immigration Offices will not isdsue it on a tourism entry stamp.