Is A wrong or B?

Ann is being unreasonable. That is not what Bev meant when she told Ann she'd give her a lift if she needed. She should have called Bev to ask before she bought the parasol and if Bev had said no then she should have either left the parasol or ordered a taxi, which is what she did.
Or if she knew she wanted garden stuff she could have asked Bev in advance when might be a convenient time to go to the garden centre, if Bev also needed to go, or was going somewhere nearby.

I’m sure when bev said if you ever need a left she meant because Ann has a hospital appointment in 3 weeks, not because she wants to buy something heavy and bring it home this moment

Would the garden centre have kept (stored) the items until Bev could help collect them?

Also is Ann really going to throw away 60 years of friendship for the cost of a taxi?

Ann ses to have taken Bevs offer far too literally. Where its a favour for a non emergency, the implication is always 'if its reasonable / convenient'. The same way, if your neighbour said that you were always welcome to pop round to borrow sugar or whatever, it wouldn't be reasonable to ring on their doorbell at 2am to ask for sugar, or throw a massive strop because the neighbour couldn't spare any at that particular moment

How on earth could Bev possibly be the one in the wrong?

Ann is very hard work.

I'm surprised that, in all her years of non-driving, Ann was annoyed at calling a taxi as she "never does that usually"!
Agree with others; Ann could easily have asked the garden centre if they could put the parasol aside up to a date that suits them, then ring Bev to ask if she would be willing to pick it up within that time frame. If both centre and Bev in agreement, fine. If not, get the taxi or leave it. But fall out with Bev? There may be a back story here...

I'm not sure it take a unanimous MN post to know that Ann is being a dick for being pissy about

Ann is treating Bev like staff.

It would have been kind to ask Bev if she fancied a morning at the garden centre with her.

It would have been OK to call Bev from the garden centre and say that she was thinking of buying some things and would she available to pick her up.

But just calling and demanding immediate pick up is unreasonable and getting in a huff is even worse - ever Uber drivers can turn down rides.

It's obvious who you are! Your sister is being very unreasonable. (I don't know you btw, just this sounds like what's going on.)

Ann is a cheeky wee wanker.

A discount parasol is not important enough to expect a friend to drop what they're doing and drive you about. At the very least Ann could have phoned Bev before buying it to find out if she could pick her up with it, and then she'd have known that a taxi was part of her choice before buying it.

Ann should have phoned Bev before purchase to ascertain if a lift was available before she committed to buying: a friendly conversation could have led to it being picked up later (perhaps Ann could have had a cuppa whilst she waited) or another day which wouldn’t have been difficult to arrange with the garden centre.

However, Ann should really know how to take a taxi: it’s a cheaper way to get around than owning and running a car.

Ann also needs to a) rememebr her manners and b) remember that she isn’t a stroppy teenager* who’s parents can’t give her a lift

*of course this statement is not saying that all teens are stroppy or petulant when lifts aren’t readily available…

Should have phoned her friend and asked before she went to the till and paid for the items. End of.

Surely the garden centre would be happy to keep the items for a couple of days whilst Ann sorts out getting them delivered?

This. Most usually do this, if they don't offer deliveries. Seems like a poor business model not to.

Re your question OP. I'm not sure of the relevance of Ann and Bev's ages - except that I'm assuming there's something more going on, because it seems odd and ridiculous, and very sad for either of them to throw away such a very long friendship over something so small.

Strange for Ann to expect Bev to be available on 15 minutes notice. After 60 years of friendship, it's unusual behaviour.

So I assume there's more to it because surely neither would want to throw away 60 years friendship over something silly like this.

Ann, a lift would be prearranged or if available you can't expect someone to just be available and drop something straight away.

I'm going to attempt it.

Bev is clearly being controlled by her DH. I suspect Ann realises this and so is upset that Bev can't get out to the garden centre because of this. Ann is more upset that Bev can't see this and get out from her coercive partner even though he wasn't mentioned at all.

I really wanted the twist in this story to be that Bev went and bought the parasol for herself.

I don’t think plants are ever easy to get home without a car, and the parasol and base are an additional problem. I don’t think Ann gave much thought to anything to be honest. It might have been ok to ring and ask if by chance Bev was free with car, but if not, accept this gracefully and get a taxi or make arrangements to pick up later. Being not very nice to Bev in any way seems extreme, and rather a trivial way to punish a 60 year friendship. Being unable to cope if you don’t get your own way needs addressing, otherwise friendships and help from others might just dwindle.

Bev is the wrong clearly. Ann is not a personal taxi service.

There is no possible chance that anyone is going to think Ann was reasonable, not even on Mumsnet where there's generally an obliging contrarian.

It was very odd to buy the parasol without checking Bev's availibility first. Ime, people who don't drive generally plan so they don't end up stuck.

Anyway, shame to throw away 60 years of friendship. Hopefully Ann regathers enough self awareness to apologise.

As someone who can't drive, Ann is a dickhead.

Ann was angry Bev didn’t pick her up and reminded her that Bev said ‘if she ever needed a lift’ etc

That's an invite to make future requests, not demands.

Ann hasn't called and asked for a lift on Tuesday to go shopping. She's called and demanded a lift right now (it was a demand not request as she'd already bought the item which would mean she HAD to be picked up).

Totally UR by Ann. An invite of future lifts isn't the same as pledging to be always instantly available at any time required.

Ann of course. She should have called Bev and seen if she was available, rather than assuming. I don't think there's anyone on earth that is always available at a moments notice.

Bev isn't a taxi