my maid of honour is unreliable... help please!

There is no easy answer to this I'm afraid. Ultimately you'll have to go with your own instincts. I can tell you that some version of this is very common - different people having different ideas of commitment, and what matters, how to resolve time-clashes, etc. If she's not overly set on being your Maid of Honour perhaps you could have her as a regular bridesmaid instead, so if she lets you down at short notice it doesn't have quite the same impact. Whilst as the bride you probably care a great deal whether you have (say) 2 bridesmaids or 3, in reality nobody else is really likely to notice!

Best of luck with your tricky situation.

What is it you've asked her to do that she couldn't come along to? My expectation of bridesmaids is to come to dress fittings then turn up on the day, no pressure or hassle or taking up much of any precious time they have off work. Remember that it's your wedding, not hers. Not everyone in your life is going to be as excited or as enthusiastic about it as you are. Does it really matter if she doesn't come to your hen do? It's not like you're never going to see her ever again if she doesn't come to it. Don't ruin a good friendship over it.

It is so much more complicated that I have time to type here, this is the over all jist of everything but she has been so negative about everything.

she told me she was jealous of me cos I'm "growing up" and she isn't, at 26 I find that a little pathetic to be honest, if the shoe was on the other foot I would be thrilled for her and wanting to help in any way I can!

At least she was honest with you and came out and said that. Not many people would admit that. Sounds like she is struggling with her emotions over it all. I'm not saying that's right or wrong but maybe she's worried she'll let her true feelings show or she'll something she regrets and that's why she's not coming along to things.

I would give her the benefit of the doubt and try and have a proper chat with her and get to the bottom of why she's behaving this way. She might not even realise the impact it's having on you.

My Maid of Honour has a job, a 1.5 year old and has just moved house. She has turned up to dress fittings, is planning my hen and will say a speech on the day. And I am absolutely amazed she has managed to do all of that and to be honest I wont/can't expect any more than that, as she really has a lot on. And has been incredibly helpful where she can be.

Your MOH is working and doing a degree - that cant be easy. I am unsure why there is an issue with her boyfriend, to be honest I think a lot of people will always put their SO over other people when it come to prioritising time. I wouldn't feel too hurt about that.

Maybe your MOH needs to start managing your expectations slightly - as she's probably not been 100% honest about all of her commitments, for fear of disappointing you.

Also, of course she can be jealous of you growing up! I imagine going to university and being surrounded by people at least 8 years younger than you can be difficult. And maybe, despite doing something that will be great in the long term, might seem as a backwards step. And as you are going to get married - clearly moving forward and taking on one of the main "adult" mile stones, you can see why she might be worried about being left behind.

People express their feelings in all sorts of ways.

Maybe ignore wedding stuff with her for a little bit and try and do something that's just for the two of you. I understand its easy to lose all your free time to planning the wedding but maybe she'd appreciate some quality time with you and you'll be able to suss out why she's being so tricky.