Hi Graham,
I do not know if you have been in contact with The London Douglas spares regarding your dipstick, I know that we have recently sold our last one, however there is a new batch on the way, I doubt that the delivery will take more than a couple of weeks.
Regarding the breather, do you have a spares catalogue for your bike? The breather mechanism is a simple mesh mounted in a steel tube pressed into a housing in the front timing cover, it is clearly shown in the spares book exploded diagram, item 2 on plate 5. if you do not have a copy I think you would find it most useful particularly as the Club spares use the works part numbers for ordering components.
Coincidently!!! I look after the supply of these together with the instruction manuals and if you contact me via my email (email envelope below the avitar) I will arrange supply of copies. The Club charge a small amount for these, the proceeds go to maintaining our archives and future production of handbooks.
Regarding the "lump" on top of the timing chest, these appear on the early Mark 1 crankcases, the actual reason is a mystery to most of us! If anyone out there knows the actual reson for them I would like to know. However, they are nothing to do with the breather.
If you do decide to buy either the spares book or the Mark 1 manual please let me have the frame and engine number so that I can be certain which manual you need.
Please note, The Club only sells spares to members, but do sell the books to non members. If you are not a member we hope you will consider joining us.
Dave