W810i SMS using more than one message?

Hi, excuse the ignorance, I'm an old git so not really well up on these things but whenever I send/reply/forward a txt, quite often, it takes two or sometimes three messages and as I'm Pay and Go, its costing me!! So, I was wondering if there's some setting I need to adjust?

..also, I received a txt from a shop today and although I don't have their number in my phone, it came up with the shop's name, presumably, I can do likewise with some setting somewhere?

..and one last question - if I purchase a Pay and Go phone locked to say Vodaphone can I then get it unlocked at my local 'unlocker' so I can use it on my O2 Sim (this is way cheaper than buying a phone free to any provider)?

all help/advice much appreciated!

The phone informs you when you are about to exceed number of characters for each message (the number ~20 appears in the upper corner of the display). But if you type one message and phone send two or three messages, that may happen if you are using national chars in your messages. While writing new message press "More" > scroll to the bottom of the list > choose "National chars." > and set it to "off"

I don't think you can use text titles for your messages, and do you really need it anyway? (don't need to answer)

Yes, you can unlock it to work on any provider's network. W810 is very easy to unlock on your computer (for free of course), there are tutorials on this site