There must be, right?!
Trouble is our bathroom is a really awkward shape - tbh I can't imagine how you'd fit a bath, a sink and a toilet in there in the first place (it's a 60s house so I think it was originally an extension of the bedroom and the outside office that he's refusing to complete was the outhouse). Basically we've got a corner cubicle shower - slightly bigger than average, but definitely not a fancy two person one, a sink cabinet and a toilet. And space for one person to move between the three things.
At this rate the poor baby will be having a bath in the living room in front of the fire XD
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It's more than his reaction is "lets throw more money at this!" not "lets ask the lady we've paid to tell us this"