There aren't any Giles homebuilts on the UK register, although the One-Design has gone through the PFA system.
I have previously bought a homebuilt in from Sweden and had the one month allowed by AWN52 before getting a UK permit through the PFA.
The Giles certainly fits within the parameters that the PFA are allowed to administer, but as a 'first of type' would require investigation by them to get approval of the design.
That is going to take a bit of time and money, but is, in principle, do-able.
The full list of currently accepted PFA types is at:
http://www.pfanet.co.uk/Engineering%...0by%20Type.pdf