Very simple deluge issue from a beginner

I'm trying to get the lead owner's mobile number to auto fill into the Lead when a lead owner is assigned.

when i run the code with an Info output i get "Null" and when i map it to the lead i get nothing.

I'm sure its simple but I'm lost .

any help welcome

Thanks

leadowner = zoho.crm.getRecordById("Leads",leadID);

LOwnerID = leadowner.get("Owner").get("id");

LLowner = zoho.crm.getRecordById("Users",LOwnerID.toLong());

Lmob = LLowner.get("Mobile");

mp = Map();

mp.put("Lead_owner_mobile",Lmob);

update = zoho.crm.updateRecord("Leads",leadID,mp);