adding nodes and POIs to an existing way

I’m trying to neaten up the Kennet and Avon canal and get all the locks in there. It’s a truly magnificent piece of engineering and subsequent renovation, so a truly worthy task.
How do I add a point onto a an existing way ?, i.e. add a lock gate ?, lots of the locks are missing, or add an extra node to a pathway so as to refine the path ?.
Sorry for such a dumb question.

Hello Mark!

Here are the answers:

Potlatch 2:
To add a point to an existing way, select the way and shift+click at the desired location. Adding more points will help realign features and smooth curves.
see also https://wiki.openstreetmap.org/wiki/Potlatch_2/Primer#Basic_Edits

JOSM:
You can add nodes to the middle of a way by going into (A)dd mode, and clicking on a way segment at the desired place. Return to (S)elect mode afterwards, unless you are building a connecting way. To add another node along this way segment, be sure to clear your selection before adding again. Take care when adding nodes in a situation where lots of ways are nearby (criss-crossing or running in parallel) It’s quite easy to accidentally add a new node which bunches together several ways. Undo! The easiest way to avoid this, is to temporarily zoom right in, so that things are spaced out nicely.
There is another trick for adding nodes to an existing way. Look out for the little crosses appearing midway along the segments. You can drag these to quickly add a node without leaving select mode.
see also https://wiki.openstreetmap.org/wiki/JOSM/Basic_editing

Merkaartor:
You can insert a new node into an existing way to give it a smoother path or to otherwise add a detail to it. Again, use the menu command “Create, Node” and put the mouse cursor on the location where the new node shall be inserted. When hovering an existing way segment, it is highlighted. Now you can click on the path to insert the node into that way. The new node is automatically inserted into the way and moving the node around will also modify the way path.
see also http://merkaartor.be/wiki/merkaartor/Documentation#Creating-a-new-node

There are no silly questions, only silly answers.

SHIFT click!, damn it,
many thanks

I’ve got a couple of other canal specific ones, the locks are numbered, some of them even have names (at Devizes they are all named in honour of people who helped in the restoration)
can/shall I just add extra attributes lock_number and lock_name ?.

I would use lock_name and lock_ref as suggested in https://wiki.openstreetmap.org/wiki/Key:lock