YMS visa for the UK- NEED HELP ASAP!

Hello,
I have been emailing the WorldBridge VAC everyday for the last few weeks and they are proving to be VERY unhelpful. If you ask 6 questions they will unclearly answer 1 of your 6. The following questions are ones that they have not answered and I can't find any info on. If anyone knows where I can find the answers to these questions or someone I can contact that doesn't charge to talk to it would be GREATLY appreciated.
1) Once the visa is granted, how long do I have to enter the UK? They've told me I can post date my visa but have not told me where on the application I can indicate this. I have a vacation booked for beginning of sept and I plan on leaving for the UK in the beginning of October so i need my passport back for my trip. They've told me I can post date it but then tell me not to apply more than 3 months before i plan on traveling- so they're contradicting themselves.

2) Can I fly with ANY airline to ANY uk airport?

3) My mom has legally changed her name from her birth name. I've asked them if I should put her birth name or legal name and they've only said you can choose to put/leave out any info you choose- not helpful eh?!

4) Do I need a written letter or email with the details of the people I am staying with upon arrival to the UK?

5) Besides my passport, bank statement, passport sized photograph and biometrics, what other paperwork must I submit to them?

Thanks

I just recently recieved my YMS visa and im travelling to the UK on may 17th so i may be able to help with a couple questions.

1) I was told that you have up to 3 months to enter the UK...but when applying for the visa it says that u needed a bank statement no later then one month before you intend to leave so you almost have to apply within the month u want to leave. I applied on a wednesday, got an email confirmation the next day on thurs saying it was sent off to Ottawa then Friday i was told by email that my visa entry clearance has been issues and by monday i recieved my passport back. So its very fast and efficient assuming all the paperworks done correctly.

2) Yes u can fly to anywhere in the UK, the visa is for UK entry clearance, so anywhere there's a custom's point u can fly into, and use any airline. Im flying into London Gatwick with Air Transat when i go.

3)I would put the name that appears on her birth certifercate unless she was issued a new one.

4) u dont need a letter but im staying with my boyfriends family when im there and his mum sent me a letter stating she was a british citizen, how i knew her and that im not incurring any expenses while im there and her address and original signature. I find it helps when you go through customs. Also i included it when i applied at Worldbridge in toronto and they didnt return that letter with my visa/passport but returned other paperwork, so it might help out.

5) as for other paperwork, i submitted a letter from the person i was staying with, you need to print off the application forms which are found on the worldbridge website. the VAF9 form and appendix 7 which i had readily filled out and good to go when i went. youll get your biometrics done when you go to the worldbridge office in toronto (or whatever office your closest to)

It was honestly a very smooth process and quick once i had all my paperwork filled out, the appt only took 20 min at most and i was done, and got my visa very fast, and right after booked my one way flight and now im just waiting to go! 12 more days lol

Hope that helped a bit!