Not sure how old Jarvis is as I've not been on COL for a while but with regard to getting things off him. Try to exchange the article for a treat. Never chase him to try and get the article back otherwise this effectively rewards him by making it into a fun game! Similarly when you put the lead on him, call him reward him if he comes and say "good boy" and then command him to sit and reward him if he complies and then ask him to wait while you put the lead on. You need to be controlling him, not the other way round.
It is essential to start practising basic training with him - always reward good behaviour and ignore the bad behaviour. Five minutes a day doing the basics will pay dividends.
