I have just come on here to start a new thread about this but you have the same thing i have just serviced mine putting 10/40 in and when cold its around the 50psi area but once warmit is about 8-10psi on tick over then about 28psi driving at about 30mph in 4th/5th gear

Can you adjust the oil pressure ? as just dont like the sound of it on tick over as it gets a little tappy