ERA5 ensemble mean and spread

Datasets and Usage C3S - Datasets and Usage
1

I try to download ERA5 ensemble data. Through the download form I submit the following request (the variable and time selection are arbitrary):

request = {
    "product_type": [
        "reanalysis",
        "ensemble_mean",
        "ensemble_spread"
    ],
    "variable": ["10m_u_component_of_wind"],
    "year": ["2024"],
    "month": ["06"],
    "day": [
        "01", "02", "03",
        "04", "05", "06",
        "07", "08", "09",
        "10", "11", "12",
        "13", "14", "15",
        "16", "17", "18",
        "19", "20", "21",
        "22", "23", "24",
        "25", "26", "27",
        "28", "29", "30"
    ],
    "time": ["12:00"],
    "data_format": "grib",
    "download_format": "unarchived"
}

The file being produced contains the 10_metre_U wind twice: once at a 721x1440 grid and another one at 361x720 grid. From its values I assume the first is the reanalysis and the second the ensemble spread, but the variable attributes give no clue if this is the case. Moreover, the third varable requested (ensemble mean) is not included at all.

Do I do something wrong? Any help in accessing ERA5 ensemble data much appreciated