Non-UK residents can only undergo a limited number of checks, such as Photo ID Verification and Watchlist Check (previously known as PEPs, Sanctions and Adverse Media). For Source of funds, Identity Report and Credit Report checks, you must be a current UK resident, as these involve cross-referencing various UK-based sources and databases.
If this applies to you, then please let your contact at the requesting organisation know that you cannot complete certain checks due to your non-UK address history.