What the policy covers, precisely
Financial loss arising from the enforcing authority's action under the statutory contaminated land regime. The trigger is formal — a remediation notice, or notice of intent to serve one — rather than the discovery of something unpleasant in the soil.
Contamination you cause yourself is excluded, and so is anything outside the insured use of the property. A policy issued for a dwelling is a policy for a dwelling.
Cover typically runs for a long but finite period for owners, and for the term of the mortgage for the lender. It passes to later owners, which is what makes it useful on a resale.
The parts people do not read, and should
<b>The Statements of Fact.</b> The policy is issued on the basis that they are true. If they are wrong, the insurer may not pay. Here, the seller was asked to confirm them and did — and that confirmation is part of what you are relying on.
<b>The Additional Conditions and Additional Uninsured Matters.</b> On this kind of policy the standard loss wording is commonly replaced, and the replacement defines what is actually covered. The uninsured matters list defines what is not.
<b>The policy amount.</b> You may be asked to increase cover if you later sell at a higher price. Whether that is necessary depends on the policy's own wording, which is a reason to keep the certificate somewhere you can find it.
The Lexsure wording ends by saying that its own summary is not exhaustive and does not remove the need to read the policy in full. That is the right advice and it is worth taking.