Vauxhall Zafira engine cutting out

Can anyone help me? I have a brand new 09 plate Zafira, in the colder weather, it cuts out, you feel a small jolt, battery light flashes on and power returns as quick as it started. This is going into the garage tomorrow for the 4th time and I am getting fed up with it now. 1st time it went in, no problem detected on machines, but battery connections found to be loose, so they tightened them up, 2nd time it went in to garage they found a problem with the EGR valve so this was replaced, 3rd time, couldnt find any problem. Now after keeping a log and car cutting out 7 times on one journey it is going back in tomorrow. The garage sees it as an intermittent fault and I am feeling we are getting fobbed off. Called vauxhall, not much joy although they are going to try and sort out a hire car, called dealer, no luck and finance company are helping the most. I am also annoyed that we bought a zafira as we have 4 kids and what is the courtesy car they are giving us.... a CORSA, great eh???? So vauxhall have said they will try and sort out a hire car but no guarantees. Is there something else we could be doing? Or is it just us and everyone else has no problems, if you did what was it???