As I have gone through your brief, I understand that you just need the amendments (normally 5-10 extra events added and 3-5 taken out) in your existing HTML.
Then Yes, I can do it in 65 GBP but still I would need to discuss with you so that we can finalize the deal.
I'm well equipped in PHP, MYSQL, JavaScript, JQUERY, AJAX, designing through Adobe Photoshop, including HTML5, CSS2/3, Bootstrap (responsive sites).
Look forward to hear back from you soon.
Thanks