Your plan sounds like a good way to go, I always try to have more room available for travelling than is strictly necessary.
I'm surprised you can't alter your booking even at this relatively late stage - most of the big car hire companies will accept changes/cancellations up to 24/48hours before the booking start nowadays, so you'd normally have a couple of days left to make a change. Who did you book with ?
I'd be sure to check their policy on changes, it might well be you can actually make a change, but that they just dont want to accomodate any alterations unless you stamp your feet a bit - you know how helpful british staff can be...
And if you havent paid anything in advance, you could simply blow your booking off. An
Avis rep told me once that even if I hadnt called, at all let alone a few weeks before it was due to start, to cancel a booking I had, nothing would have been charged to me, and thanked me for letting them know ! Dont feel bad about possibly doing it, they wouldn't think twice about changing your booking if it suited them...
A quick glance at the Dollar website gives a weekly rate of £279 inclusive for a 7 seater Dodge Caravan picked up at Sanford, against £ 210 for a full size 4 door car, so that suggests you'd be looking at between £ 70 - 90 a week more. How do those prices compare to your existing booking ?
They need 48 hours advance notice for a booking, so you still have time to book if you need to, having pitched your other company. If you want more info go to the UK site - it allows you to book for locations abroad but gives the prices in Sterling (enter Sanford in the pick-up/drop-off location box):
Dollar Car Hire UK
Another alternative which gave good prices was the Airline Network website - they use Dollar and had some good rates:
Airline Network
I'd also suggest you try Alamo at :
Alamo Car Hire UK
I've found them cheaper than Dollar of late, and have booked with them for my family's next trip to Orlando.
Hope this helps !
