Michael
– ready mix French polish will work well, though the bottle caps can be a nuisance, as they all seem to be the childproof variety. It is readily available in hardware stores, and you may find a choice of colour tint available.
– Raw linseed oil is much slower drying than boiled, which is processed and has driers added. I was taught that Raw should be used for outdoor applications, such as garden tools, structures, etc., with Boiled used for fine wooden furniture, tool handles, gun stocks etc. Raw seems to develop a deeper amber colour over time. In practice, I have used both for everything, including wiping over the bare steel parts of garden tools, and did not note any adverse effects. A true woodworker will probably disagree with me!
– Python file handles seem to be still readily available from various tool dealers, and last forever. I prefer the bare wood which soon acquires a dark workshop patina as the grime is transferred from hand to tool. When making my own handles I have found beech very reliable, easy to turn and readily available from old furniture. Years ago I was given some Boxwood which I used for small handles, wonderful stuff, but may not be an economical choice now. Ferrules from copper , brass, steel tube, I used to collect any odd ends just for this purpose.
Dave