Where it is not that simple
<b>The business may have been taken over.</b> Developers merge, are bought and transfer their assets. If the benefit of the covenant passed with the undertaking, the successor can enforce it — so “the company is gone” has to mean gone and not absorbed.
<b>The benefit may have been assigned.</b> A covenant's benefit can be transferred separately, and there are companies whose business is acquiring exactly these rights.
<b>Property of a dissolved company can pass to the Crown.</b> Where it does, there may still in principle be someone in whom the benefit vests.
None of that makes the usual conclusion wrong. It means the conclusion rests on what the search found rather than on the company being hard to contact.
What to do with the answer
If the position is clear, it is clear, and no policy is needed. That is a better outcome than insurance and it is worth asking your conveyancer to state the basis for it in the report, because the next buyer's solicitor will want to see the reasoning rather than repeat the work.
Where there is any doubt — a successor company, an assignment, a covenant whose beneficiary is a person rather than a company — indemnity cover is the ordinary answer, and the ordinary rule about not approaching the beneficiary applies.
Keep whatever evidence was obtained. A Companies House extract filed with your deeds is worth having in fifteen years' time.