A good rant from MJ
Presumably aviation systems track EGNOS in Europe these days?
The 430
W/530
W and all the Garmin IFR ones that came later can use EGNOS.
Whether they can use it today I don't know. EGNOS has been transmitting for years but with a "test" flag active and all IFR approved GPSs were banned from using the signal with that flag set. Only handhelds like the 496 could use it. Then Eurocontrol finally approved EGNOS for "safety of life" ops and that flag should have gone away but due to some Brussels cockup it didn't, and this was quite recently (months ago). It may be sorted now.
EGNOS is not currently operationally relevant, because GPS without SA is easily accurate enough for everything short of LPV. As for LPV approaches,
AFAIK the UK has only one of those, in Alderney.
EGNOS is relevant when it comes to integrity checking. I don't know the details but vaguely recall that in the USA if you are receiving WAAS (the US version of EGNOS) then you can proceed with a GPS approach even if a RAIM check does not compute - or something like that. If/when I need to know about this I will check it out; my current GPS (KLN94) is not EGNOS capable anyway.
Re GLONASS, I am not aware of any current IFR GPS which can receive the signals right now. It cannot be hard to do and "should" be possible with just appropriate firmware... unfortunately Galileo and Glonass are not simply extra satellites to supplement the American constellation. They are on slightly different frequencies, etc.
What people also forget is that the Americans are updating their satellites too. The various wild claims for Galileo accuracy and reliability are all based on the Navstar system remaining as it was when originally launched in the 1980s.