In the building/contracting industries and others where technical disputes often delay payment, the fear of large legal costs deters many firms from suing for their money. Some debtors are suspected of keeping disputes running if they think a supplier cannot afford litigation.
Insurance cover can be available for legal expenses if you have a good case. A broker's help is advisable for negotiating terms. The building industry, for example, has an insurance scheme at Lloyds for members and non-members.
It is important that unpaid sellers feel confident of having disputes settled in court if needed. If debtors are told that legal costs are not a barrier because they are insured, disputes may well be settled quickly without going to court.