Two issues- a grant has to be obtained to the owners estate before closing - only your solicitor can ascertain how far along this is.
Secondly the title is not registered, ordinarily this would not delay completion but here sounds like there is an issue, not clear exactly what that is so again only your solicitor can advise.
Normally closing a house purchase 6 to 8 weeks nowadays, closed one a few weeks ago within 5 days ( that was with clients hand delivering papers between offices and both vendors solicitor and purchasers solicitor dealing with it as priority due to hardship of client).