https://warwick.ac.uk/study/international/immigration/student_route/applying-for-student-visa/healthsurcharge#section5
"However, if you made this visa application within the UK, then you will be eligible for a refund for any overlapping IHS payment for periods of 6 months or more. Any overlapping IHS payment for a period of less than 6 months will not be refunded."
但我唔知你個 case 係咪真係冇, 所以我話 check 清楚!