Do oval handles suit a certain type of player more, or is it just personal preference?
I would say your current bat is a mid-low sweetspot. I think the Lithium is a mid placed sweetspot, so that would be a good shout. 
Yep a Vantage Lithium at 2lb 9oz or less would do very nicely!
Very nice, they sound awesome. Not sure if I'm a fan of the stickers on the Lithium though, much prefer the LE stickers (white).
Hi mate, we are VAT registered so can apply that VAT deduction for you. We have numerous bats in stock that could be suitable for you. Take a look, here: http://www.itsjustcricket.co.uk/cricket-bats-c17#c18 You can filter by weight/price/brand/colour etc. by using the tick boxes on the left hand side, which should make your search easier. If you still need some advice, please do fire me a PM and I'll get back to you straight away.
Cheers,
Paul
Nice, I've checked out your site, will do so again.