If you can't find a match for your imported transaction then it is most likely that the corresponding transaction has not been entered into Landlord Vision, or it's been allocated to a different bank account. If it's a mortgage payment, check that you've recorded the payment in Finance Manager => Mortgages/Loan. Also, to see exactly what transactions have been entered into Landlord Vision for this bank account go to Account Manager and click on Bank Accounts. Click on the bank account you are talking about and then on the Account Transactions tab; compare this list with your imported statement found under the Bank Statements tab (actually click on the statement name to see all of the transactions you've imported and not just the ones left to reconcile).
Hope this helps.