@hafniumzinc, thank you for some great input. WOL looked so easy and I only use it for my own PC I moved it to the top of the list to get done, seeing it was low hanging fruit. The expires binding being merged into core makes total sense as it is SO awesome.
I still have some playing to do with OH3 to get comfortable I feel. I think returning to a new install as suggested by @rlkoshak is a good way for to get back on the horse.
From your deletion process I did it in complete reverse and tried from the binding going down to the items, and to Rich’s earlier points it is an unusually use case to want to delete iit all and not keep some of it for reuse. I guess I am sick of looking at the clutter in my 2.5 version and looking for ways to improve on my clean-up activity as soon as it becomes too much of a chore, I know I will end up leaving the debris behind, as I am quite lazy when it comes to configuration tidiness.
@rlkoshak I do indeed use apt so I will give your suggestion a try, Thanks!
I have been reading a LOT about the MQTT migration and seen a few contradictions in amongst the same messages, this has led to the confusion I suspect. I will take a look at the links you have provided and see if I can get some more clarity, along with my plan to baseline and snapshot I should start to make progress.
Your response to #9 was interesting, my current plan of attack was to operate my OH2.5 system in parallel to OH3, some of the common bindings that could allow for multiple connections to external accounts or were simply to use on two systems simultaneously I was looking to do up front, some examples are, openweather, ntp, network astro etc…
Items that have small well package use cases can be done either at the begining or the end, for example icloud, http and execcommand come to mind.
The items that are fundamental for my setup are,
MQTT, Zigbee and AmazonControlEcho binding most of work is in this area and where my playing needs to get me comfortable. I was considering these three areas could be migrated room by room, as every room has at least two if not all three items present.
The timeofday I guess is now the scheduling section and I need to look at that before I start the migration too as I have quite a lot of cron triggered rules.
I think no matter how I do this migration it is going to become messy at some point and so getting the playing right upfront is going to help me when figuring out what’s gone wrong when I migrate. This is certainly a fork lift upgrade for me and I need to make sure I am as ready as I can be. And just to pitch in amazon completely screwed up my smart devices and groups yesterday as I obviously need more issue to look at whilst still on holiday
As voice input is my main form of using my home I need to divert my attention to getting the echo stuff sorted ASAP as I had not touched it in weeks I can think its something they have played with on their side
Which means I can end up ‘fixing’ it at my end and they change it a gain at their side that breaks it again, you have got to love it 
Thanks guys for some great assistance and helpful comments.
Paul