Simon,
I take no issue with your airline of preference. All airlines would want want to garner a positive sense of loyalty and preference from anybody who flies with them. It is a competitive business and one that relies on perception, experience, marketing, and confidence. However to be fair, the problems you descibe can and do happen to every airline within a particular market segment.
Airliners are extremely safe and reliable, but they are also complex beasts that operate under a strict manufacturers and regulatory framework. When a fault occurs downroute, it can sometimes happen that there is no local engineering support for that aircraft type, and more commonly no local availability of spare parts necessary to rectify a problem. When this happens, a whole host of people are involved in arranging to get that aircraft back into service as quickly as possible, and this involves an astonishing array of logistics. Of course it all happens out of public view, and to that end is nothing more than a hugely inconvenient delay, with seemingly nothing happening anytime soon.
Even at major UK airports, there is no guarantee that a part will be available locally, and the process of procurement will often result in a significant delay. Some airlines (such as Monarch) do operate with their own group in house engineering company which may be an advantage on ocaissions, but all companies will contract to an engineering company that should provide a similar service.
The problems you describe whilst relatively rare in combination, are all familiar situations to people who fly everyday. An aircraft is dispatched in accordance with a Minimum equipment list, and a dispatch deviation guide, and sometimes this results in compromises albeit safe ones having to be made. For example a seat armrest being secured by gaffer tape may look a little unsightly, but the option of perhaps a 6 hour delay to a 2 hour flight with any subsequent disruption is a commercial one that is made every day in every company.
Another reality is that once a customer is irritated or annoyed by a situation, event or perception, they will rarely look for other good aspects to an operation, only further confirmation of what they already believe. We all do this to some degree, so it is not unusual.
Every airline in the world would pay homage to their deity if they could avoid these sort of problems in isolation or in combination, but the truth is they can't. To some degree it is simply a question of numbers or luck as to your chances of experiencing this type of thing because it happens to them all.
I am happy to agree with you, but in the interests of fairness this has to be said.