Multitasking is good-- it helps that the G810 has 128 megs of RAM, though the Spb enhancements eat into that, there's still enough left for reasonable multitasking (5 apps running is fine, I haven't met a WinMo device that can handle 20 apps running).
Like all Windows Mobile Pro devices, the Toshiba has handwriting recognition-- both print and cursive.
It's too soon to judge battery life, I'll include that in the full review.
Lock and unlock the phone-- you mean the screen and buttons? By default only the power button turns it on, and that's recessed so it's hard to hit accidentally. In fact it takes work to hit it intentionally. There's also the usual WinMo Today Screen lock function.
Looks like you're in the UK, where it will likely be cheaper than here in the US since it's sold directly into the UK market. I believe Toshiba said the list price was $525US back when the announced it in Feb. at Mobile World Congress. Since this is the first week it's on sale (and not at many shops) the price is signficantly higher, but it will drop.
Editor in Chief, MobileTechReview