IFTTT location trigger has become useless with Android 8.1

Since updating to Android Oreo 8.1, I'm now finding all IFTTT location commands are taking an age to trigger effectively now rendering it useless for heating and outside house lights location commands. So, we're now getting home to a dark cold house, then the heating and lights come on about 10-15 mins later, pointless. Previously the exact same triggers were instant and reliable, we'd be sat in the car and the notifications would sound at exactly the same place every time (about 5 miles from home as per the instruction).
I've followed remedy instructions by IFTTT (I think they know this is a problem), got Data saving off, battery saving off etc etc. The only thing I haven't tried is a reset of the phone.
Anyone else experiencing this??, any ideas??
thanks

PS I'd like to try Stringify, but appears that Evohome is not supported, although many other Honeywell thermostats are.