Thanks very much for all of the replies, they're really helpful 
I am allowed to bring my own, I double-checked with the hospital and they said it would be fine, well, they'll use a sterile one to dry him, then wrap him in mine. I stupidly forgot to ask them which sort of blanket though, hence this post. 
I realise the blanket is likely to get covered in vernix, blood, poo, sick a combination of/all etc, I just want something to comfort him asap before I get him back. Also, I have some neurological issues from an accident several years ago, so they aren't sure how my arms will react to the anaesthetic and it may be that DH has to hold our little man for a while, which makes me all the keener to have him wrapped in a blanket which smells of me.
I'm going to be formula feeding, so although I want skin to skin contact asap, feeding won't be immediate. Great idea about a blanket for when he's in the cot though, I'll snuggle one of those too
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InPursuit no you haven't bummed me out at all thanks
I realise most of what I'm doing is about making me feel better/comforted, baby probably won't give two hoots. It's been a very difficult and complicated pregnancy and we've had several losses before, so this time I'm just trying to get all excited and reassure myself more than anything. Also we've asked for the weighing and vitamin K to be delayed for a while, again hospital said no problem. This is all ideal world scenario though, any emergencies and all this goes straight out of the window.
Lastly our hospital seem to have all towels/blankets in lilac. I abhor the colour lilac, it's an abuse PTSD trigger for me, and although it doesn't really affect me that these days, there is no way I'm having our son wrapped in anything lilac.