Question mate.

Do you park near trees at all for any length of time? If so, the recent week of hot weather might have dotted your car with tiny droplets of sap, as all the trees sprang into life.

If that is the case, I would say it needs a good citrus (soft stripping) foam, wax free wash, clay, rinse, polish (if needed) and wax. You will know after the clay if you have got the stuff up.