If there's no way of replacing your lost vaccine record, you should try to get as many vaccines as possible done before the visa medical. There's a limit to how many vaccines you can have on the same day!
I think the flu vaccine is the only one that you need to have had this year... the rest are all long-term (e.g., a dose every decade), so there's no risk of getting them too early. You just need to ensure that you bring the record to your medical appointment.