Hello Ewan,
Had you seen that married "26" years (crossed out) before? I thought it might have some significance as to what had happened 26 years earlier - or 26 years before the date of Wm's death. I also thought her occupation might be significant - a skilled job which she might have been involved in (with Wm?) pre-Isle of Man.
Regarding your checking for Alice Emily's birth, no doubt you have seen:
www.isle-of-wight-fhs.co.uk/bmd/startbmd.htm
I found that I could put only the first forename on to get a result, and then check through those looking for an Alice Emily. I looked briefly and found an Alice Emily Bull b.1865 registered Ryde, and several registered Cowes.
You said you were starting with 1867? Do you mean searching the years earlier from that date?
Sue