Here is a draft reply to Mr Bramble:
Dear Mr Bramble,
Re: Interview for MSc in Computer Science
Thank you for your letter of 15 June offering me an interview for the MSc in Computer Science program. I am pleased to accept the interview scheduled for 30 June at 2pm.
However, I would appreciate it if the interview could be arranged for one hour later, at 3pm, due to train times from my home. This would allow me sufficient time to travel to your university.
Please let me know if the later time is suitable. I look forward to discussing the program in more detail at the interview.
Yours sincerely,
[Your name]