Graeme Fowler again followed up with Garmin regarding the lack of EGNOS signals with the GPS V 2.50 update. Garmin swear blind it’s not them, citing the following:
As the EGNOS signal is still in its test phase the European Space Agency who engineer and control the EGNOS satellites can switch the signal on and off as they see fit. Currently they are broadcasting on the Indian Ocean satellite, which only just reaches the UK with its signals. This will mean that it is difficult to pick up EGNOS signals as the European satellites are currently not broadcasting.
Which I suppose sounds like a reasonable explanation. The Garmin representative also suggests checking the ESA‘s Satellite Applications page for updates on its current status.