Chris, this was a great find. It's so simple to prepare, then watches itself. I don't own a slow cooker, so I cooked this in the oven for 4 hours on 150c (fan forced) We rarely get frenced shanks, so I used normal ones, and I used the chilli paste for a nice bite.
I did 4 shanks which only just fitted into my crock pot (3 on the bottom and 1 on the top) so I did need to open the lid to move them around a bit for even cooking which I did twice and after 9 hours on low they were falling of the bone so tender and flavoursome. The only thing was I did not have any fresh tomatoes so used a tin of whole peeled tomatoes (would do again but drain them as there was so much liquid in the end so I scooped some out into a pot and thickened with a cornflour slurry to make a lovely sauce to go over the shanks), thank you Chrissyo, made for Name that Ingredient tag game.
Wow this was wonderfully tender and the sauce had a great flavour over mashed potatoes. Only change I made was to use a tin of roma tomatoes with most of the juice drained rather than fresh. I think the chili paste is worthwhile and it adds a very subtle flavour that wouldn't be too strong for anyone.
Threw it all into the slow cooker and left it to do its own thing. Tasted lovely, but next time will use the chilli version as needed a little bit of kick.