Long story short, I found when I was in Orlando that I can get a very good discount off of Garmin products, so I had a look.
As you can see from the picture the discount drops the ForRunner 945 to £337.99 instead of £519.99, the Fenix 6X Pro with the 51mm face (but without the sapphire glass) drops for £488 instead of £750.
The 245 Music I bought my wife as an early Christmas present is £195 instead of £230.
Even though my Garmin is only just over 2 years l'm inclined to upgrade, I'm justifying this to myself because I'm starting to run for longer and further than I ever have before in my life.
I'm really not sure on which to go for, they are both excellent pieces of kit and yes, I know the 945 is based on the Fenix 5 but it includes a lot of the tech from the Fenix 6 range, i.e. the wrist ox sensor.