(Even as I wrote that, a wee voice was mocking me, "Ooh, working in a cafe, la-di-da!" Apparently it's pretentious, or at any rate quintessentially bourgeois, to do this - according to the chippy wee voice in my head. Yet somehow J. K. Rowling managed to sell the fact that she wrote in a cafe as a marker of her poverty! It's her equivalent of the flight to Egypt! That's why she's a marketing genius, and I am but a lowly shrub in literature's knotted garden.)
* IKEA - twenty minutes' walk from here - is a good bet. No wifi, and free coffee on weekdays. Back when my children were small, I'd take them to the ball pool there, which they loved, leave them for an hour's free entertainment while I worked and drank IKEA's free coffee, then collect them. Everyone was happy except IKEA, who at least had the bliss of ignorance. And to be fair, my walls are now lined with BILLY bookcases, so it came right for them in the end.