Oh Claire! It really is time they started looking into this more seriously. To be honest, I am not surprised that they could not give you instant results...I think that is usual, but you really don't want another weekend not knowing what is going on.
teh person who should be doing this pushing is your GP (I think!) but they don't seem to be helpful. In limited experience of hospitals and A=E, I would say that you do need to go back to them, during teh day, during the week and get stubborn. The right consultant should be available during the day, during teh week, so may come and look at you, or at least give the A+E staff some advice. I realise that you can't just turn up at A+E, adn I not suggesting that you falsify symptoms at all, but if you are getting readings like you describe, I am guessing that NHS will direct you to A+E anyway? If at all possible, push to see the correct consultant while you are at A+E. Sorry, I wish I could help...I can do polite but stubborn quite well.
Or as said above, the GP...you are obviously worried about strokes. I also agree, just turn up if you can.