On 30 Aug, 09:58, "John Vanini" wrote:
....snip....

I searched the sites of two other seed suppliers (Marshalls and Mr
Fothergill's) but they don't list any such varieties. I've emailed both of
them to ask whether, in their opinion, such varieties exist and, if they do,
will the seeds be in the supplier's catalogue next year.

Two suppliers of less common varieties are
'Seeds of Distinction' www.seedsofdistinction.com
'Seeds by Size' www.seeds-by-size.co.uk

I have used both suppliers and am happy with their service.

Tom