Ok well I bit the bullet and now have an answer to my own question. If you have a Sigma M30 alarm and need a new remote, get the SIGAC110. I just picked up mine from the post office and it works a treat. Smaller and neater than the old remote too
So, on to question 2...
My Sigma alarm no longer controls the lock on the drivers door

It only locks/unlocks the passenger door. The OEM central locking does work though, if I flick the rocker switch both doors lock/unlock. Same if I use the key in the door, or the actual plastic lock pin on the driver's side. So why doesn't it lock from the alarm then??? Anyone else had this? I had it intermittently a while back but it cured itself, now it's come back again
*edit:
I should probably add it's not the new remote that caused the onset of this, it was happening before I programmed another remote in.