I lived and worked there for years, and have sadly outlived old Ben, the original B.J., and his son Rob, and now the yard is run by Rob's son.
'Can do' (even if we have to invent a way to do it) was the way it was, and I hope that that spirit continues.
In the winter commercial work on the craft you see plying the Thames full of tourist passengers around the Tower of London and Westminster is the mainstay, but in the summer, the 'do it yourself' season, docks are available, and you can either work yourself, hire the boatyard's experts, or utilise a combination of the two to get your boat fettled and back in the water.
If you should ever go there to get your work done, look at the tree covered, uninhabited Isleworth Ait that you are moored next to, and imagine me, strolling around naked (I've fancied nudism but been a bit shy) in summer sun on what at the time was for me my own private public island, then slipping into the warm summer water of the Thames to cool and float with no more than about a 20% chance of killing myself through careless drowning. Such antics are no doubt far from your mind as you select somewhere to have a new bottom on your narrow boat, but you could choose many worse places.
You can contact the yard on 0208-560-4848, the number of times I have picked up that phone and said foureight, foureight, is legion, and I hope you may call and speak to someone who will try to be equally helpful.
I have no commercial relationship with the yard, and sadly. living now as far from the sea as it is possible to get in England, do not even have a ship of my own.