Bernard
I took photo's of the cloud edge when it first appeared that morning at about 0830 UTC and posted shortly after on the Weather Climate forum in an item that I called "Skies across the SW"
https://groups.google.com/d/msg/weat...o/zFJtJn3oBQAJ
I noticed the edge of what I thought was a high AC sheet as it moved down from the NW and pinpointed the edge on the visible satellite image for 0815 UTC.
Unfortunately I didn't see any of the fallstreak holes which occurred further east.
Looking back at the observation from the LCBR from the Exeter Airport AWS I can see that AC had a very high base indeed 23,000 feet!
03844 - Exeter Airport
United Kingdom 31 M AMSL [50.7 N 3.4 W]
AAXX 10154 03844 46784 /0503 10132 20047 30219 40252 57014 333 55300 20465 83/56==
AAXX 10144 03844 46683 /0606 10133 20041 30225 40258 56016 333 55304 21099 87/44==
AAXX 10134 03844 46683 /0306 10147 20044 30228 40261 58018 333 55310 21955 81/39==
AAXX 10124 03844 16981 /0707 10137 20057 30234 40267 58013 69921 333 55310 21894==
AAXX 10114 03844 46982 /0506 10129 20062 30241 40274 58003 333 55310 21699 81/73==
AAXX 10104 03844 46978 /3302 10105 20078 30246 40279 56002 333 55302 20897 88/73==
AAXX 10094 03844 46736 /1901 10091 20078 30247 40281 55000 333 55309 20930 81/56 87/73==
AAXX 10084 03844 46767 /3502 10056 20055 30244 40278 58001 333 55310 20305 81/56==
AAXX 10074 03844 46763 /0502 10036 20035 30248 40282 53001 333 55300 20015 87/56==
AAXX 10064 03844 16761 /0602 10033 20031 30248 40282 54000 60002 333 20006 3/101 55088 55300 20000 70000 88/50==
AAXX 10054 03844 46763 /3202 10012 20009 30245 40280 56005 333 55300 20000 83/50==
AAXX 10044 03844 46959 /3503 10024 20021 30246 40281 56008 333 55300 20000==
AAXX 10034 03844 46862 /0302 10028 20025 30248 40282 58008 333 55300 20000 81/57==
AAXX 10024 03844 46860 /0402 10020 20018 30250 40284 58008 333 55300 20000 81/57==
AAXX 10014 03844 46902 /0301 10025 20021 30254 40288 58004 333 55300 20000==
AAXX 10004 03844 16860 /0202 10035 20030 30255 40290 58003 60001 333 55/// 21148 83/57==
As an observer I still would have reported it as AC but with some exotic height of 16,000 feet or so.
Bruce.