Thanks for the replies,
Before taking up MA I didn't do any exercise, and even as a child I had poor leg flexibility.
I'm a "rural" estate agent so as well as sitting in a car or at a desk I spent quite a lot of time walking around fields etc.
Thankfully I haven't visited the chiropractor for a over a year but I had a recurring back problem, I'm sure training has lessened the problem and now when occasionally it does flair up it heals quickly. It makes sense that the hamstrings probably were the root of that problem too. My recent visits to the sports massage guy were due to a shoulder strain and while there he tried to work my legs but I left with a groin strain and haven't been back since.
Currently at 38 I'm more flexible in most areas than I have ever been but I'm about 18 months away from black belt and my leg flexibility is hampering development of some techniques I want to to master before I get that far.
My aim to do whatever it takes to reach my full range of motion within the next 6-8 months, so that I have time resolve bad habits I've developed, trying to kick beyond current abilities.
Yes, I must spend more time sitting holding my toes

, and I do like that sliding foot exercise, should be easy to do on my laminate floor. I can see that would have great potential to strengthen and improve flexibility for both front and box splits.
I'm also going to try a yoga video which a friend has offered to lend me, but I'm open to any suggestion and would really like to hear from anyone that has successfully overcome a similar problem.
Cheers
Nic