I note that the R.E.8 is still on the NZ Register as ZK-TVC
http://www.regosearch.com/aircraft/nz/TVC

Which Albatros is it?
Albatros DVa-1 ZK-TVD has a Star
Albatros DVa-1 ZK-DVA has a Crescent
Kermit Weeks’ has a lightning bolt (it would have been on the ZK register during testing)

http://rnzaf.proboards.com/index.cgi?action=gotopost&board=airshow&thread=15057&post=144516

The (UK) CAA will allow foreign-registered aircraft (which meet home country requirements e.g. the NZ CAA’s) fly in the UK for a limited time (at least up to a season, it would seem).