I'm just back from a holiday in Madrid. Booked long time since and I was hoping when the CL draw was made that our first fixture would be Real away, but it wasn't to be.
Instead I was out there when Basel played. First thing to say that unless the Swiss keep a very low profile the vast majority of then must have done a day trip on the Tuesday. There was no obvious sign of any of their fans around Sol, Plaza Mayor or Plaza Santa Anna on the Monday night, nor did any of them seem to be around on the Wednesday.
The biggest contingent I saw must have been about 200 or so drinking in a couple of the bars ringing the Plaza Mayor, a couple of hours before the match, but it was all low key - no singing and no banners. In fact you wouldn't think a big European match was taking place that night. Few police in attendance but mainly looking bored. Big group of fans were in the middle of the square drinking from cans and that didn't seem to be a problem as far as the police were concerned. Worth noting that they're doing a bit of work to some of the buildings in the square and there's some hoardings up, but it's business as usual in the remaining (many) bars.
Plaza Mayor is still probably the best place for everyone meeting up but my favourite is Plaza Santa Anna - better bars serving better beers! They're only five minutes walk away in any event and both close to Sol Metro station for getting up to the Bernabeau.