But, if you are not able to get a definitive diagnosis soon indicating for certain whether you have UARS, another option is that you could just go ahead and try CPAP therapy. If CPAP relieves your symptoms then you will know that the symptoms were caused by UARS/sleep apnea. However, if CPAP does not relieve your symptoms that could mean either that you do not have UARS and your symptoms are caused by something else, or that you are not using CPAP effectively enough. (It can take some people a lot of time and effort to figure out how to optimize their CPAP therapy enough to start feeling the benefits from it).
As you say, it seems like you need to get another sleep study and make sure they are really measuring RERA's this time.
I would be surprised if there isn't a sleep lab in Europe that can diagnose UARS. Maybe you should try contacting all the sleep labs that are not too far from your location to ask if they can detect RERA's and diagnose UARS. Maybe you will find one that can do this for you and is easier for you to get to than Stanford.
I am not an expert, but my opinion is that, based on your description, you should get checked for UARS. Although you do not wake up at night, if your sleep study indicated that you are having 40 arousals per hour, then clearly your sleep is very disrupted. But I do not think there is any way to be confident in a UARS diagnosis before a sleep study has been done with detection of RERA's.
In order to determine whether you have UARS, you will need to get a sleep study done at a sleep lab that uses esophageal manometry. An esophageal manometer is the instrument used to detect respiratory effort related arousals (RERA's), which are the key indicator of UARS. Most sleep labs do not use this instrument, but Stanford Sleep Medicine Center pioneered the diagnosis of UARS, so you could go there for a sleep study, or else contact them to ask if they can suggest a sleep lab in your area that uses this technology.