Alarm and immobiliser on Merc E200 2 litre...?

I have had problems with my alarm going off in my car for a while, so I locked it manually without putting on the alarm system (to prevent it going off). However, on Saturday, the car would not even open when I pressed the key fob. I bought new batteries and still nothing happened (the alarm is the one where it is housed in the drivers mirror). Today, I called RAC home start out and hoped they could help. They were really helpful and told me that sadly, with this type of alarm system, the only way is to go to the dealer and have it all done as the red light which is usually on the mirror and key fob no longer works. Trouble is, my car is in a lane at the back of the house and it cannot be towed as it is too narrow to turn a towing vehicle in the spaces provided behind the houses! Also, I am furious that just because of an alarm system, my whole car is useless, cannot be driven or even towed away - crazy alarm system!

I have to find some strong men to push it onto the road side for me, but before I do, has anyone else had this problem and been able to disconnect the alarm system (which RAC said they could not do on this model) and immobiliser?

Any serious answers much appreciated - I have to go to Surrey tomorrow and at this rate I am going to have to borrow my daughters Ford KA, which will get blown up the motorway in this weather!

Thanks.

:)