It's a Question of Time - The Mystery of Karen Shuttleworth's Age

1970 was a busy year for John Shuttleworth, perhaps the busiest we know of - he triumphed as Wishee Washee at the Dinnington Alhambra, married, became a widower, was involved in a crazy road accident and met his second wife recuperating. The other key dates in his life are somewhat harder to judge.
It's clear his sole agent Ken Worthington doesn't move in next door until some point after his 1973 New Faces appearance but we never establish exactly when.

We also know that Darren, John's son is a teenager legally allowed to work in Victoria Wine by 1993. We can extrapolate a birth date somewhere around 1974-1975 from this. We also know John's younger daughter Karen was inspired by Band Aid in December 1984 to offer her tangerine to the starving. As Karen was then aged 10 it appears Karen was also born before the end of 1974, meaning there's probably around a year between the pair in age. However, at the time of the Europigeon TV special in 1998 Karen is still at school (despite apparently being 24 years old). One might argue that Europigeon involves several scenes clearly recreated for TV that had we'd previous heard occurring for real on the radio in 1994, but that still leaves us with a 20 year old schoolgirl Karen.

This can perhaps be fudged if we assume John has merely claimed Karen was on a school trip at the time of Europigeon to excuse her absence from proceedings. Perhaps he wishes to obscure details of her life to avoid his celebrity impacting on her existence, perhaps John claimed she was 10 at the time of her 1984 charitable gesture simply because it scanned better.
We know that Karen has now finally left both school and home and although Shuttleworth time seems to move slower than normal time we can tentatively assume she's now somewhere between the ages of 28 and 36. It is rumoured we may learn more of her circumstances as this current series continues.

However with John and Mary celebrating their silver wedding anniversary in 2003 everything gets completely mucked up. Oof.