Arghh! this thread has been hi-jacked, I only mentioned the harmony in post #3 as it could have been useful to send a sequence of commands for the OP if nothing else worked.
Anyway, the biggest problem is getting your head around the concept of activities. The harmony shouldn't been seen as a simple replacement for 6 or 10+ remotes.
You don't need to remember buttons as each button on the remote does what it should do for a particular activity. The configurable LCD soft buttons cover what isn't specifically printed on the actual buttons.
You set up the remote by telling it which devices you have to control. You could stop here and have a pretty pointless all in one remote that you have to switch between programmed devices.
The real fun starts when you create activities. With a single button press 'Radio 4' could be set up as switch off TV screen, switch on sound-bar or amp, set input to stereo/direct on amp, switch to freeview and switch to radio 4, adjust volume.
'DVD' could be set up as switch on DVD, put STB into standby, switch TV to hdmi3, switch amp to DVD input, switch to Dolby/DTS, eject tray and/or play disc in tray, switch 16:9 or 4:3 depending on squareness of eyes etc. etc.
The buttons on the harmony will correspond to the activity, i.e. 'volume' will control the amp or TV or freeview box depending upon configuration, 'menu' on 'watch DVD' activity will bring up DVD menu, 'menu' on 'watch freeview' activity will being up freeview's menu.
The LCD soft buttons can be configured to cover all sorts of things, the fvp4000t for example has a few buttons missing from the original remote and these missing functions, such as 'media' can be added to a soft button, menu and guide works and I refuse to acknowledge the 'home' button on the original remote and the 'plus' button for that matter, they're menu and opt on my harmony and the brilliant thing is the buttons are always in the same place regardless of device's own remote (I have a horribly laid out panasonic and also samsung remote that thankfully I no longer need to touch)
This is just scratching the surface as to what's convenient.
Programming the devices into the harmony is fairly simple, realising what can be done with activities can take hours to initially set up or, if like me as I change things, years later I'm still doing the odd tweak. I find the harmony incredibly useful.
I looked online before posting #3 and discounted the £35 model as it does not have an LCD 'soft button' screen. The £50 (600) model is over priced and only offers 5 devices and no idea about amount of activites. The 650 model makes more sense with 8 devices, but isn't available at a decent price. Some of the newer models have a battery that isn't replaceable which means cracking it open after approx. 5 years or throwing it away.
To give you an idea about discounts, I bought a new 515 a few years ago for £20 which would have been ideal for the OP. It's used in the back room to control semi-redundant equipment. I use a 785 which does everything I want and it gets tweaked every now and again as I update.
The OP, if the humax remote is struggling, would do better with an all in one universal remote for around £10 to control TV and humax or possibly a big button universal remote for around £15 again controlling both TV and humax.
So techie hat off (I know you asked Graham, but I thought I'd jump in), yes it's complicated, but well worth investing the time. Having said that though I couldn't recommend any current harmony at the moment, although amazon did have £100 knocked off an okay one a few weeks ago.
I suppose if you 'get' the harmony then you don't look back, maybe a bit like marmite.
The OP doesn't need a harmony remote and I'm sure if the hotel mode menu can be set then there won't be any need for extra button switching to display the humax correctly