Wow I didn't expect this topic would stir up such controversy. I do appreciate all the different sentiments expressed. None of them seems unreasonable to me, even if I don't share some of them. Let me respond to some of them:
1) "I have a pressfit tool, do you want it?"
Thanks for the offer, I'll get in touch when my BB fails! Hopefully not any time soon though.
2) "It's like buying anything (e.g., a sandwich) as opposed to making it yourself. If you are going to moan about the fee, do it yourself."
Fair enough, but when you go to a supermarket, you can see exactly what you are paying for. I can walk into a supermarket and decide to have someone make me a sandwich or just buy the ingredients myself or just walk out. There's no awkwardness there about what I decide to do because there's no relationship between me and the supermarket. Whereas if I walk into a LBS, I feel like I have to agree to things before I have time to consider all the options and make an informed decision. This actually happened. I went in with a damaged wheel (which as I realise now was beyond repair), and they said a good new wheel's going to cost £150. Well, I just walked out and ordered a Shimano 105 wheel online for £100 because I didn't feel like questioning them about the quote and arguing with them.
3) "We need them, so we need to support them."
I don't need them because I can do most maintenance. Bike maintenance doesn't require some specialist knowledge (by this I mean stuff like medical science or architecture). Obviously it takes much time and effort to be a good mechanic though. But you don't have to be at that level to do regular maintenance on your bike. I guess more broadly speaking I don't think I share this sentiment that we have to support local businesses. I'm probably from a different generation than many on this forum, and that's likely a major factor here. I'd happily do without local businesses on my high street. I rarely go to any of them because I can find better stuff for cheaper in supermarkets. Restaurants are an exception perhaps, but even then I don't patronise any business just because they are local and independent. They have to have something special to offer, otherwise I wouldn't be sorry when they disappear.
4) "My LBS/charity lets me to borrow tools and give advice."
This would be the best option for me. I don't think mine does, though.
All in all, what I'm unhappy with is the lack of transparency in pricing and the reliance on "building a good relationship" with people to get good service. I hope my viewpoint is not offensive to some, but I much prefer to have a strictly impersonal relationship with businesses. Yes, it's nice when you go to a local restaurant and they know you, greet you and show you to a nice table. But I'd happily let that drop for more transparency in pricing and being able to purchase exactly those items/services which I require. Really, I don't want to build relationships when I go to a shop (I do that elsewhere), I just want to buy the stuff/service I need at the lowest price possible. It's a bit of a cynical attitude I guess.