Though it looks a tad rough it sounds like the owner has just done a very thorough service and also has a LOT of brand new parts to go on it - might be a handy one for a member here - I've no link to the sale/owner:
https://www.gumtree.com.au/s-ad/kingston/lawn-mowers/deutscher-11hp-r28-ride-on-mower/1264355347