Any easy wheel designed for the Brompton with M6 bolt will fit and allow to roll the Birdy folded. The one of Riese & Müller/Pacific Cycles shown have spacers and are very wide and heavy, they make the use of any side pannier impossible.

But most of those wheels, even without spacers, are too wide to allow the use of rear pannier.

These narrow and lightweight easy wheels work to roll the Birdy folded and still allow the use of Vaude rear Pannier with any risk of heel strike (they are sold under a lot of different brand names, they have bearings under their two side washers and several brands provide them with titanium bolt).