For whats it's worth when your thinking about setting up a business, lets talk the UK, you should do your homework and try to find out if theirs a need for the business you are going into, take window cleaning, forget the car valeting, which you might be into right now, perhaps to find out if theirs any call for this type of work you do a leaflet drop, say a thousand, if you get maybe 20 or so replies you gotta say it's a no hoper. You might find no one else is doing this type of service...why not? perhaps their is no call for it...Perhaps it has been tried and failed.
Now your going to Spain, and it has to be so much harder then the UK, and i know the area you want to start up in, to me that's a lot of retired folk with plenty of time on their hands, who can do their own windows for free. Everyone is saving every cent right now.
I say forget car valeting, you have to drive to the house, it takes about 2 / 3 hours to do a good job that the customer wont complain about, if you do it in any less they wont like to pay top dollar for a quick scrub about, then you drive to the next one, say you do two a day, at a push three, at 20€ a car would they pay 30€?, x five days...= 300€ a week, any less and your in trouble, and these are no way guaranteed figures.
Doing this sort of work is a little bit like a mens barbers, he cuts 20 heads a day, every day, day in day out....he cant cut 21 a day, because the hours in the day wont allow.
Hope you do well, hope you prove me so very wrong.