SEO: Lose Google page 1, rank 1 with 301 redirect?

[Nina May]

Where I am working as an SEO the company has rebranded and launched a new website on 16th October.

I have created deep links (301 redirects) from the old site to the new, done all the usual webmaster verification etc and told google that we have changed website address.

This morning I googled our two main keywords "personalised cards" and in Chrome and IE7 we are number one on page one, and in Firefox number 4. Needless to say the Director is over the moon and I am chuffed to bits as well.

The old site remind4u com has not had a 301 implemented from the home page, you have to click any of the tabs or the central panel to be 301 redirected to funkypigeon com home page. If, say, tomorrow, we implement a 301 redirect from the old home page to the new home page, will we lose out in SERPs? And if so, for how long?