jasman

Another option is to move the site onto a new domain immediately, and 301 redirect the old domain to it. Then drag the negotiations out a little to give Google enough time to replace the old domain's rankings with the new one's.

Keep all correspondance by letter, not email. If they ask why, say you prefer to keep hard copies for all legal correspondence. Each time you send a letter, and wait for their reply, and then send your reply to that, it's going to be about another week. So if you can drag it out so several letters are exchanged you should get a few weeks while Google realizes the domain forwards to the new site. Even after the domain is in their possession it may take them a while to change the nameservers giving you even more time.

So initially you might send a letter making it clear that you will transfer the domain over to them as you respect their need to protect their TM, but don't give any details other than that. Then wait for reply. You might then reply to their letter saying something like you just need your web designer to download a backup of the website before transferring the domain over and you expect that to be in the next few days. They reply saying whatever. Then you send another letter saying you now have a backup, but ask which email address the domain should be transferred to etc. Eventually, you hand over the domain, but your new site is the one coming up in Google.

This way, instead of asking them if you can have a month to redirect the old domain to the new (to keep the ranking you have built up in the search engines), you effectively take a month - or at least a few weeks anyway. So they don't even get a chance to say 'no'. Don't take the piss dragging it out too much though, you don't want to annoy them and risk being cut off! As in all areas of life, walk a fine line...