I don't think that's unusual maxi, you may be reading more into it than was intended. The form of acceptance referred to is for the use of shareholders whose shares are held in certificated form, ie NOT in a nominee account. You can pick up the offer document, regardless of whether your shares are in nominee or certificated form, from Capita Registrars. I would expect if you held your shares in certificated form then a copy of the document would have been sent to you by them. As they do not know the addresses of nominee holders they cannot do that.
I can only speak for Barclays regarding takeover documentation and I've never received any of that from them for any takeover deal I've experienced and I suspect that is the same for most nominee account holders. (That is why dealing costs are cheaper). Shares held in nominee accounts will be voted for on the basis of the rules laid down by that company. Barclays does nothing unless otherwise instructed so my shares will not have been used to vote for. Other Barclays nominee shareholders may have returned the letter received from Barclays to vote yes and ONLY their shareholdings will have been used vote yes, the rest will not. As we learnt over the weekend the approach taken by other nominee accounts is different and the do nothing default would be to accept the deal. The forms submitted by the nominee account administrators will reflect the total of shares voting yes (or defaulting yes) and will be accepted by Redstone and reported in their initial statement.
Redstone are seeking 90% acceptance from ALL shareholders, not just those responding. The letter from Barclay's specifically said do NOT respond if you wish to do nothing (or reject the offer).
I hope this has gone some way to answer your questions maxi.