If you can do the DD then you can do a 200km Audax. I'd say that an average summer 200km is easier as it'll be completed entirely in daylight.
And if you pick somewhere ~25km away from London Fields and ride to the start of the DD you could even do both at the same time (there are ways of making your own Audaxes by getting receipts as proof-of-passage along the way). I did it last year for the DD.
Yup. That's a perfect goal to have.
If you can do the DD then you can do a 200km Audax. I'd say that an average summer 200km is easier as it'll be completed entirely in daylight.
And if you pick somewhere ~25km away from London Fields and ride to the start of the DD you could even do both at the same time (there are ways of making your own Audaxes by getting receipts as proof-of-passage along the way). I did it last year for the DD.