Yahoo Finance historical prices changing from GBX to GBP

thanks for this …
though it seems difficult to translate as google translate refuses to find the page whenever I give it the url of the howto (Quellen für historische Kurse)?

Anyway… is there a reliable and free source of historical quotes? what do other people use?

And, if I change the source of historical quotes will it work with the transcations I’ve already entered without have to edit or re-enter them?

Its a shame its not straightforward to fix.
thanks again