SOME of the leather dressings I have contain Lanolin but they are not purely Lanolin
I have a recipe from one of my customers that is a mix of pure beeswax, goose fat & lanolin - but I'd need his permission before broadcasting the exact ratio
I also have quite a collection of wierd & wonderful US Army training manuals for saddlers.
One of these is a local cavalry manual from 1918: it's stuffed full of recipes for various leather dressings, etc. that were designed to be made on-site from locally procured raw materials.
I know where this book is (unlike over 50% of my other books as we recently moved house & most of my books are still in boxes) so IF you like I am happy to see which specific recipes I can find that have the heaviest concentration of Lanolin & scan them for upload here or on my website , whatever suits you best...
As has been said many times, the tanning process is ONLY a way to slow down the natural decay of the animal hide.
If the leather becomes too dry it WILL decay.
The best hide foods & leather dressings are the ones that replicate as near as is possible the fats/oils etc. that would be present in a healthy hide prior to tanning.
Hope this helps - I'll dig out the 1918 manual tomorrow
Jon
p.s. Just noticed you are in Germany.
I have a catalogue from a German saddlery supply company - Kappey.de - I'll see what products they have in stock that may be suitable