Some cycle lanes where I live are barely a foot wide (probably slight hyperbole - I haven't actually knelt in the gutter and measured one, you'll be surprised to learn(!) - but they are very narrow) and you end up going over drainage gratings and people's discarded litter; also people park in them. I could keep swerving around but I often just give up and go in the same lane as motor vehicles.
I don't believe there's any issue with doing this in the eyes of actual road rules - as there would be if I was to cycle on a public footpath or a motorway, for example - but I know some car drivers don't like it.
I think this is more a preference than an actual issue in the eyes of road use rules. Some local authorities seem to think bicycles are only as wide as the wheels, and forget about the handlebars. There are numerous off-road cycle lanes around here with obstacles deliberately placed on them to stop use by quadbikers, motorcyclists etc. All well and good if you could actually get your bike through the gaps when dismounting, but some of them are impossible!
Sadly that's not unusual. The one I remember is from Gravesend to Rochester where they've nicely resurfaced the main lane but not the cycle lane!
Is the car dealership still using the cycle lane as an extension to its forecourt? And that's before you reach the bit closer to Gravesend where the houses are lower than the road, the cycle lane is a shared facility on the pavement, leading to a series of about 25 hump-back bridges... I choose the road!
I tend to avoid shared-use paths whenever possible now. Even with a loud and clear bell, people ignore cyclists. I would also like to see more cyclists with bells attached to their bikes and using them, to be fair.
The problem there of course is the traffic. There are very few drivers in my experience in Herefordshire who actually leave 1.5m of space between themselves and cyclists, and the amount of times I've nearly been knocked off my bike...Or indeed, the amount of close calls I've seen between cars/lorries/etc overtaking me in a dangerous spot and nearly causing a head-on collision with other traffic...
All new-purchase bikes now have to be fitted with a bell, I seem to recall, but there is no requirement to retrofit. Having bought a new bike twice in the last two years (let's just say I own two of them but only have possession of one), I'm really not sure how I managed 15 year relying on a polite "excuse me" if people didn't hear me coming. You do have to give people enough warning though, to allow for dithering - it's amazing how many people can decide whether or not to cross a road in front of a car coming at 30mph, but can't decide whether to go left or right when faced with a cyclist wheezing uphill at less than 3mph...
Edit: I forgot my reply to the second part. I believe guidance says car drivers should overtake other road users with the same caution they would another vehicle, rather than a fixed 1.5m width. Some drivers come close enough that you can almost feel their wing mirrors, others prefer a distance of "in the field on the other side of the road" before they will even pull out.
On a shared use cycle path the priority is for pedestrians. Ringing a bell does not give you priority and can be intimidating to those with sensory disabilities.
As others have said, there is no specified priority, so the usual guidance of keeping left, overtake on right, use common sense, and "do unto others" applies. The chances of coming across someone with aural sensory disabilities is really quite unlikely.
However, on a shared-use space, all users are supposed to keep to the left, overtaking to the right, and certainly not persisting in walking four abreast or wandering. I say that as more of a pedestrian than a cyclist.
Yep - basically, pay attention to other "road" users. As the German Highway code says, "constant caution and mutual consideration".
So how does say a blind user know where the bell is coming from?
Humans have directional hearing, and you tend to find blind people have much better hearing due to greater reliance on it. Also blind people will tend to be carrying a cane or similar, so the cyclist can use their eyes to determine if they should be taking a different approach with that person, such as approaching very slowly.
In the very rare occasion that a cyclist comes across a blind person, one hopes that the blind person is easily identifiable (e.g. white stick, dark glasses) and the cyclist takes appropriate action.
Last weekend, I found myself in the dubious position of having to overtake a horse on a single carriageway country lane. Knowing I shouldn't use my bell, I remained a respectful distance away until I would have been able to overtake slowly and with great caution (the rider was trying to keep left, but also to avoid the sizeable potholes and chippings thrown up from recent frost/ice). As it happened, the rider heard me ride as I cycled through some damp leaves and immediately pulled into the next passing place to allow me to pass. We exchanged pleasant good mornings, thank yous and continued on our way. So very different to the following car driver, who was so obsessed with trying to get past me a few minutes later that he failed to notice the car coming the other way when I pulled into a passing place and ended up with egg on his face. I even held my hand up in the "stop" sign to warn him that I wasn't only stopping to let him past (although would have allowed him to pull away first) - the approaching driver then slowed down to tell me that she saw my hand signal from two dozen car lengths away!