On Saturday, 22nd September, I need to catch an early morning train from Brockenhurst to Waterloo to catch the Eurostar. Is it advisable to book this ahead of time, or would just in the week prior be soon enough? I will be in England for six weeks before needing to use this train. Fares I have found at the moment are around 35GBP for two. Does this price remain the same, or would it be an advance booking fare? Seems a bit expensive, as I just paid 50euros for two from Paris to Milan. Thanks for any advice!!