I cant really add anything to Martini's post, but thought I would add some drivel anyway.
Channel Islands immigration are very very unlikely to request a passport, as Matt says currently you don't need
a passport to travel between the British Islands. Though this is set to change at some point in the middle future.
On your return to Blighty you will obviously be fine, as your other half has the stamp what says so.
I too look forward to you buying us a beer on Friday lunchtime, that is the 22nd of July.