First of all no one here will trust a newbie thus if you do have an account thats older than this one then you should try negotiating with that one ..also you aren't supposed to post here but rather in.... Marketplace section where there are services present.
Also one to one negotiation will need ID's offcourse because the market is full of scammers thus I strongly recommend anyone thinking about the deal to go through everything in detail..
Also I am a little skeptical about this ' If a BANK would rather trust bitcointalk.org rather than an offline wallet which is more secure, if you haven't thought about it then you should go and check out some wallet thats prevelant in Europe, one to one deals without an intervening authority that too.. as you said..they want to buy a lots of bitcoins is for sure not something that one should do out here like this.
Also its a really bad time to buy
because right now the value of bitcoins is gonna sore high thus I don't think anyone would be ready to sell.