Hi all, I've been continuing my research at The Keep (East Sussex Records Office), but don't have much to report. The DH family were not on the electoral register during their time at Mottynsden Lodge in Burwash.
As background Mottynsden was purchased by Commander V in 1932, and he and his wife lived there until 1967, when they sold the manor house and moved into the lodge. Mrs V, by then a widow, died on 3/7/82. The property has stayed under the ownership of the son, DV, since then. DV owned and lived in another nearby property, so presumably rented the lodge out, but is now living there (he is listed as living there in the 2019 edition of Debrett's Peerage, available online).
As we know the DH family were listed as living at the Lodge on 1/12/84 on their chilldrens' baptism record, and then the next evidence I can find of anyone else living in it is the 1987 electoral roll, when there is different family of 4 listed as living at the Lodge. The qualifying date for this electoral roll was 10 October 1986, so we know that the DHs had definitely moved out by then.
I looked through local newspapers but they didn't reveal much. I did spot this article about krugerrand gold coin smuggling (see attached 1984 Sussex Express article), which isn't connected to Mr Wonka, but it does sound like the kind of activity he could be involved in, and would explain him parking his family in the UK and having an excuse for coming backwards and forwards from Europe regularly. I have done a UK news search and there seems to have been quite a bit of this gold coin smuggling going on in the 1980s before the VAT rules were changed, and Luxembourg was one of the countries with no VAT on hold at the time.