select top1 in subquery - part 2

Next problem....

I need to join on the items table again, but this time i need to sum on a column but only on certain criteria (look at the last join, is that the correct way of doing it?) - the column in question is EstReplacementCost


declare @date datetime
set @date = '2006-07-01 00:00:00'

SELECT j.JobNo, j.ClaimNo, nab.NatAccBranch, j.CoverID, j.NewForOld, j.AccidentalClaimType, dc.DamageDescription, c.Cause, j.ReportOnly,
                      j.ContactsEntered, j.CustDirectContact, j.CustLicContact, j.VisitedOn, j.FinalReport, cd.CustName, cd.CustPostcode, j.RoomCount, j.Excess,
             sum(ia.chnet) totalInvoice, rc.AccName, replItems.ReplacementLetterSent, SUM(estItems.EstReplacementCost) estCost
FROM         dbo.Jobs j INNER JOIN
                      dbo.LicencesHeld lh ON j.LicID = lh.LicID INNER JOIN
                      dbo.NationalAccountBranches nab ON j.NatBranchID = nab.NatAccBranchID INNER JOIN
                      dbo.DamageCategories dc ON j.DamageCatID = dc.DamageCategoryID INNER JOIN
                      dbo.Causes c ON j.CauseID = c.CauseID INNER JOIN
                      dbo.Items i ON j.JobNo = i.JobNo INNER JOIN
                      dbo.ItemActions ia ON i.ItemID = ia.ItemID INNER JOIN
                      dbo.CustomerDetails cd ON j.CustomerID = cd.CustomerID LEFT JOIN
                  Items replItems ON j.JobNo = replItems.JobNo AND replItems.itemid =
                  (select top 1 t.itemid from items t where j.JobNo = t.JobNo and replacementcompanyid is not null and replacementletter is not null order by Replacementlettersent desc ) LEFT JOIN
                  ReplacementCompanies rc ON replItems.ReplacementCompanyID = rc.ReplCoID LEFT JOIN
                  items estItems ON j.JobNo = estItems.JobNo AND estItems.ItemID in
                  (select t.itemid from items t where j.JobNo = t.JobNo and replacementrequired = 0)

WHERE     (lh.LiveUser = 1) AND (j.BUID = 2759)
GROUP BY j.JobNo, j.ClaimNo, nab.NatAccBranch, j.CoverID, dc.DamageDescription, c.Cause, j.ContactsEntered, j.CustDirectContact, j.CustLicContact,
                      j.VisitedOn, j.FinalReport, cd.CustName, cd.CustPostcode, j.RoomCount, j.Excess,newforold,accidentalclaimtype,reportonly,
                  rc.AccName,replItems.ReplacementLetterSent
HAVING      (j.FinalReport > CONVERT(DATETIME, @date, 102))