Ive learnt abit more since i posted, if you just jailbreak it shouldnt touch yor baseband, it will only alter your bootloader if you used Ziphone, which can now be reversed using pwned.
I've had to restore mine as since it was jailbroken it would randomly stop being seen in windows(i would get a "USB device malfunctioned" message). I've restored it and it seems to work ok now.
So maybe my iphone really doens't like being jailbroken!!!