Not necessary. The Embassy shall interview you by the phone.
Yes, it could. Authorized persons need to provide authorized letter, receipt and ID card
Presence at the time of filing is required to all applicants.
The necessary requirements for UK visa include: having inviters, the applicant should have stable job and how their income is, are they owning houses, lands and other properties, bank capacity, family factors, outbound history…other additional factors.
Generally UK visa is valid within 6 months, multiple entry; maximum stays of 180 days.
Normally the processing time for UK visa is from 3 to 4 weeks, except for the cases of humanities and emergences.
The applicant may apply at UK visa application center in HCMC and Ha Noi.