we have booked car rental with dollar, I booked this with the flight centre. we haven't had much experience with car rental and I booked a compact ford focus or similar car. there will only be my husband and I, but now realise that we wont get our two large suitcases in the boot. we are not travelling until October. should I change my booking now to a bigger car or wait until we go to pick it up and hope that we can get an upgrade then.