Hi
I dont know why your car would stop when you were moving already but it could be a faulty new battery or the connections to it may not be right.
I had a similar issue with my landie and it turned out the wires were on the wrong way round so when it should have been charging the battery, it was actually discharging it. That said, whilst it didnt start on a regular basis, it never stopped once it was already going.
I would recommend a new garage - but sorry cant help with anything in the mean time.
Sue
October 2013
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