This appeared in our front lawn back in June. It looked like a foxglove but not like any foxglove I'd seen before. I did have a cursory look in the books to see if I could find it but failed to find it. Reviewing the year's photos I came across it again and this time I've found it. It's Straw Foxglove, Digitalis lutea, an introduced species that has naturalised in the south of the country. It's actually rather rare, as this BSBI map indicates, and there hasn't been a record in Sussex since 2010 when it was noted in Brighton.
The flowers are distinctly those of the Figwort family, Scrophulariaceae. The most striking feature is the extremely hairy corolla.