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Yes she came back in, shortly after the slanging match.
At least she seems to know where to run to. We'll all just have to tread carefully when she's out there to avoid making her panic and wind up on the bloody railway track. There is nowhere a catflap could be put in, it's all metal doors and double glazing, we'll just have to hope she can be called in when we need to lock up. It's a totally unsuitable house for a cat IMO, I said this from the beginning but was largely ignored.
Thanks for the advice folks.