I'm fairly sure that under German rules such a company (single director, Germany based) would be treated as German. Thus all taxes would need to be paid in Germ

I'm fairly sure that under German rules such a company (single director, Germany based) would be treated as German. Thus all taxes would need to be paid in Germany. You'd have double accounting, and have to file (manually) null accounts in the UK to satisfy Companies House, and file actual accounts in Germany. Royal pain in the ass.