Considering you have nikon lenses, it may cost you less if you upgrade to D7000. It has the same sensor as k5. There is no visible difference in IQ.

My second battery which i mainly use in the grip lasts a bit less than the other.
But that's because it is transferred from my k7 and is 3years old. Still i am able to take like 1500 pics with two batteries, so no complains I rarely do such amounts in one shooting. When both batteries were fresh and new i did recharge them once for 2 or 3 months. Now i do that more often as i have macro lens and i do a lot of LV focus.

btw what are your settings?
How much seconds before the live review turns off? 3 or 5?
or... what is your 'metering time setting' ? I've noticed when it was set at 10 seconds the camera lasts much more than when set at 30secs.
Btw k5 has very low ''turn on to shot'' lag so after a shot i switch it off if i think that the next shot will be 30secs or more from that time.

I know how frustrating is that battery issue. Back in the days when i had k200 i tried more than 5 sets of new batteries with different chargers and my best number of shots were no more than 150 ... in the summer. In the winter it was like 30. No difference if they were envelops or ni-mh. Only energizer's lasted 800+ shots, but they cost a lot. That was the main reason to sell it even it was an AMAZING camera.

B&W images are SUPERB!
Well done!

I thought i mentioned it... but clearly i forgot...
Cheers, bforbes.

It is some kind of mission impossible with pentax and teleconverters.
Let's all hope they will fix that soon.
Btw I bought 2x Cobra TC for 6quid last week and I am amazed how good DA*300 performs with it. Of course there is IQ loss, but i think there's a little detail gain in some cases. But then again... focusing at 600mm is kinda hard. I got it now for mostly static objects, and i am close enough to say 'i can focus gulls in flight towards me'.

I can post pics if somebody is interested in results.

sigma teleconvertors don't work with sdm.
The only tele convertors that work with sdm are those which have Pz in their name, which stands for power zoom, and they are not good enough. The AF is slow and hunts just too much compared to bare lens.
1.7x Pentax AFA is maybe the best, but not cheap and it focuses not the lens.

Pentax have 1.4x in their lens roadmap for end of this year or 2013 i'm not sure.

Go for 300/4. it is a cracker lens! I prefer it compared to 200/2.8

Any ideas where i can find kingfishers or bee eaters near Southampton or around Hampshire?
Cheers

Rumors are 2500-3000$

I do like the pictures, just making a comment, what i think is wrong with some of them.
Cheers.

Am I ?

No problem mate
Just my opinion.