A nice fully detailed email confirmation of my reception of MRCC Bilbao, Spain, on 2187.5 kHz. I sent them both an email (2nd attempt to firstname.lastname@example.org ) and a letter. From the answer I guess that it was the letter that made it to the control room.
Whereas Valencia, Coruna and Las Palmas Radio are frequently heard with DSC messages, the MRCCs seem less active on MF. There are quite a few of them though, but the ITU list indicates a presence on VHF/UHF only. Classaxe however shows five stations that were logged on 2187.5 kHz in recent years: Finisterre, Tarifa, Gijon, Valencia and Bilbao. The first two are most frequently heard apparently.