“The only slight annoyance is that sometimes on start up it displays the previously issued discrete squawk code rather than 7000. This is despite 7000 being selected following landing.”
That is a known firmware bug. If you get your unit upgraded to 2.5 (the latest one?) it will go away.
If you are replacing a KT76a + with a Trig and you want ADSB out you need to cut an additional hole in the old KT76a tray and wire it up to an approved GPS. In the UK it is not legal to use a hand held or an unapproved (ie permit) installation. This is a very silly rule!
Rod1