What I do is use my IPad to do this part. You have the option to take the photo directly via the form and then automatically gives you the right resolution. Using a PC will not help you here
I used to avoid sending from Wise over the weekend as it would be slower due to some normal banking links but normal Monday to Friday always minutes to transfer.
International driving licence not required if you have a Thai driving licence. Normally the internal licence has your home address linked to your home country licence
No issue just fly in. I am a Brit too. You don’t need to apply in advance. If you want 90 day then yes organise before you leave ( circa £150).
I used to make at least 2 x 60 day a year
Unless it’s changed google advises
You can visit Thailand for a period of 60 days for the purpose of tourism, business engagements, and urgent or ad-hoc work. This visa category can be extended for another period not exceeding 30 days. You can also apply in advance for a multiple-entry visa for up to 60 days.