Johnny Jarvis videos and DVDs have previously been available on eBay but listings are now being removed before they complete. I've got both if anyone wants to see them again. It's a great series and every bit as good as I remember it 20 years ago. From what I've read on the web, the original BBC tapes have been either wiped or lost so it's unlikely that it will ever be re-leased or re-broadcast.
And I recently got hold of "One Summer" too - I've always associated the two series together as they were broadcast around the same time in the 1980s and made such as impact on me!