Brendan, I quite understand your position, but he may be unaware of the strength of feeling, and there's no benefit in cutting off your nose to spite your face. So, as I use both platforms, I have emailed him anyway, saying:
"Dear Anthony
Well done on including a full text search in the latest update to the iPhone app. It's a very welcome enhancement. Do you have plans to roll out similar functionality in the Android app?
Last time this issue reared its head might have been a few years ago, when the iPhone app included the glossary pages while the Android app didn't, which was a pity. I think you may have mentioned then something about the availability of embedded PDF viewers on Android, but I'm not a software developer so I don't know the exact constraint.
No doubt you are aware that the split between usage of iPhones and Android devices is pretty much 50/50 in the UK, so there is a sizeable army of Android users who feel disenfranchised by having an inferior version. Is there any chance you could possibly revisit it? I know it would be greatly appreciated.
Kind regards"
I'll let you know if and how he responds