Thanks Warin, that's really helpful and I will go and have a look at some Garmin maps aa you suggest. In principle I am happy with OSM.

The question list is also really helpful and here's my thoughts:

What do you need in a GPS unit?

Waterproof.
Readable in the sun.
Battery charging. (Assume this means i can charge the battery on the bike)

YES, DEFINITELY FOR ALL

What do you want in a GPS?

ability to have a map? YES

colour display of map? PREFER

ability to record your track (you past path) so you can back track? NO

ability to follow a pre-set route? YES

ability to recalculate a route if you go off course? YES

ability to warn of speed/red light cameras? NOT NEEDED BUT OK

a flash memory card storage so you can swap maps without a pc? NOT SURE - YES IF NEED TO CHANGE MAPS

Portable - so you can use it while walking? NO

What else?
Don't need voice/blue tooth
On bike charging mount that's rugged and works (and option to buy two to cover both bikes)
Ease of use, especially on the IT

If you had a shortlist of 2 or 3 what would be on it?

Cheers
Andy

Sent from my iPhone using Tapatalk

It is unlikely that you will find a GPS unit nowadays that does not have a slot for flash memory.
Maps are always expanding so you can never have enough memory space - always double up on the amount of storage space that you think might be sufficient (I bought a 16 Gb card initially and now use a 32 Gb).

Slightly off your topic, but I continue to use a "water resistant" mobile phone that does everything that I want from a navigation system - I navigate and it assists me.
"It" is this software:-
https://www.mapfactor.com/en/

__________________
Dave

Ive been using the garmin montana 610 all through western europe, balkans, and eastward through Turkey, Georgia and Armenia. Ive added an sd flash card (8gb) and downloaded open street maps and the tet maps as well. Great little unit, water proof, rugged, and you can wire up a powered ram mount for charging. And easy enough to plot routes either using the unit itself or using the free garmin software.

Quick update and plea for guidance:

In the end I opted for the Gamin Montana 610. Got a new one, including GB OS 1:50,000 mapping for £391 from Blacks.

I spent a slightly frustrating Saturday trying to get my head around how to make it all work.

So far I have loaded Garmin Express and BaseCamp, and then added in OSM mapping into BaseCamp to compliment the OS map.

I tend to plan routes in Google maps. I have exported these as .kmz files and loaded them directly into BaseCamp and also used GPSvisualizer to covert them to .gpx files before loading to BaseCamp. I also looked at loading the .gpx files directly but was not sure where to put them on the Garmin folder.

I can open the .kmz and .gpx files no problem in BaseCamp, when they show as a track.

I gather I need to covert these to a route to get route guidance. When I double click the track and select "create route" it gives me an error message. I am using streets in the middle of Bristol - so not sure why it is erroring.

I can create a route by changing the BaseCamp profile to direct routing - it then does not error, which seems odd. However if I then change this profile back to "motorcycle" it takes the route all over the place.

Essentially I want to do two things:
1. Create a purely 'on road' route in Google maps for a typical week tour (split by days) and make it a route on the Montana where I can get route guidance on my selected route
2. Create a trail riding route (mixture of on and off road routes) that does the same

Any tips on where I am going wrong?

Cheers
Andy

Nice chatting Andy- I hope you are now on the right track.
Do get in touch as and when you get [] moments!! and I'll try to help.
atb