I predict I will eventually see Great Spotted Woodpecker in Robin's garden!
Haha come on Chris that's a banker!!! Try again... ;-)
I'll go for Iberian Chiffchaff, Glossy Ibis and a Great White Egret (for Holme, not the poach - with several already)
Ok more seriously I will be bit braver than Andy! (are any of those even BB rarities anymore!!?) I'll go for a Red-footed Falcon past the cliffs in the Spring, a Red-flanked Bluetail in October & a Desert Wheatear late autumn.