I made it a CTE as in below:

CTE (comments, matter_uno) AS

(SELECT case when isnull((SELECT top 1 i.comments

FROM

BO_LIVE3.dbo.HBA_SOURCE_BUS i INNER JOIN

BO_LIVE3.dbo.CXA_FOLDER_OBJECT j ON i.FO_UNO = j.FO_UNO INNER JOIN

BO_LIVE3.dbo.HBM_NAME k ON k.NAME_UNO = j.OBJECT_UNO

inner join BO_LIVE3.dbo.HBL_NAME_CLASS h on k.name_class_code = h.name_class_code

WHERE i.MATTER_UNO = a.MATTER_UNO and ref_source_code = 'LEN1'), '') like '%DEBT:%'

then

ltrim(rtrim(replace(replace(replace(replace(replace(substring(

isnull((SELECT top 1 i.comments

FROM

BO_LIVE3.dbo.HBA_SOURCE_BUS i INNER JOIN

BO_LIVE3.dbo.CXA_FOLDER_OBJECT j ON i.FO_UNO = j.FO_UNO INNER JOIN

BO_LIVE3.dbo.HBM_NAME k ON k.NAME_UNO = j.OBJECT_UNO

inner join BO_LIVE3.dbo.HBL_NAME_CLASS h on k.name_class_code = h.name_class_code

WHERE i.MATTER_UNO = a.MATTER_UNO and ref_source_code = 'LEN1'), '')

, 6, len(

isnull((SELECT top 1 i.comments

FROM

BO_LIVE3.dbo.HBA_SOURCE_BUS i INNER JOIN

BO_LIVE3.dbo.CXA_FOLDER_OBJECT j ON i.FO_UNO = j.FO_UNO INNER JOIN

BO_LIVE3.dbo.HBM_NAME k ON k.NAME_UNO = j.OBJECT_UNO

inner join BO_LIVE3.dbo.HBL_NAME_CLASS h on k.name_class_code = h.name_class_code

WHERE i.MATTER_UNO = a.MATTER_UNO and ref_source_code = 'LEN1'), '')

)), 'WALK-IN', ''), '|', ''), '£', ''), '¬', ''), ',', '')))

else

'0'

end , a.matter_uno

FROM BO_LIVE3.dbo.hbm_matter a

Then I have a column from the select as follows ct.comments AS Lender1_Debt

E.O