Yes, exactly the same.

Unless it has a CofA, a UK PtF or an EASA PtF, to the UK CAA it's just a pile of parts, not an aeroplane.

G

AFAIK, in the case of LSA, "experimental" refers to amateur built, from a kit or plans.

Pre-LSA factory built "fat ultralights" were granted an experimental certificate, because they did not have a U.S. or foreign airworthiness certificate. Not much chance of getting one of them approved here.