Thanks David..
Been so busy after the 'Dorothy Cock-up' that have not pursued further..
I'm way behind times in digital detail ..
but old fashioned design philosophy makes me think that there is an inherent failure within your remote..
not experienced by the thousands of other users..unlike problems such as
well remembered 'Silver Ion Migration' and 'Membrane Failures' in the early Electronic Exchanges..
Battery voltages are palliative i would suggest in your case..
although when younger i would have done just as you..

Hence i could not resist partaking in your Quixotic Grail..
so I dug out a pair of 10 YEARS OLD NICAD batteries and charged then for 30 mins..
they said 1.3V so I stuck them in the Humax remote and
Voila.. still works from some 20 feet away..Windmill collapses

My wife still uses her SKY Remotes which are AV arranged such that they over-rule
everything..
hence i see no need to get a Harmony..as we now no longer leave the house for weeks at a time..
and i just accept that the Power-Fail Bug will still get me one day.