I agree part of the problem is with the app error routine, it doesn't actually tell you what it doesn't like, " No TIU found" is a useless message, because in actual fact it can be found because it runs the other engines !
As I said I am happy, I just posted in case there was something glaringly obviously amiss with my setup.
Having been in the IT business for a long time working with Networks it is true to say that adding an iPad to WIFI and a WIFI to TIU does add to the potential for handshaking problems which I think is what is going on ,the fact would appear to be that the error routine in the WIFI doesn't have the ability to recover from the error it gets presumably from the TIU, it needs for me to switch it off and on again to clear the problem.
Just to be clear the MTH WIFI is for the most part is a cool option, and the iPad app is great to use, far easier to swap engine than with the handheld remote, also at my age easier to see with the large screen! Ok so maybe the odd bug, but never the less for the price a value item.
As I said in my last post running most of it with WIFI and the odd engine by remote is not a big deal, so back to having fun with my O gauge buddies!