So, now nearly 100% shinny. Pretty dirty inside. Now open/close much better.
Best cleaning product was Bar Keepers Friend. 500ml spray. Got the Stainless clean bar some deep corrosion that it could not deal with 100%. Have left that as it is not critical.
Will rebed with PU40 from toolstation. However only on the front and rear screw areas as I do not see the point of the middle and this seems to block a drain hole and help muck accumulate.
I used a PTFE lubricant spray on the lever and cam spindles and it improved the function very well. Use the extended nozzle to get in close and direct the spray at the pivots, just a very small squirt, operate, repeat, until you have a very nice action.