The biggest discounts carry the biggest risk, by design
A property priced 20–30% or more below comparable value usually has a specific, identifiable reason — and it's rarely just an eager seller. Before treating a large discount as good fortune, work out exactly what's wrong, because it's very likely something structural, legal, or financial rather than cosmetic.
Short leases
A lease under 80 years triggers marriage value calculations that make extending it significantly more expensive. Under 70 years, many mainstream lenders won't mortgage the property at all, which shrinks your buyer pool to cash purchasers when you eventually sell — itself a discount on your future exit price, not just your purchase.
Structural issues
Subsidence, structural movement, and non-standard construction (concrete, steel-frame, or certain prefabricated systems) can all make a property difficult or impossible to mortgage conventionally. Get a full structural survey, not a basic valuation survey, on any property where the discount looks unusually large for its condition.
Legal and title problems
Restrictive covenants, unresolved boundary disputes, missing planning permission or building regulations sign-off for previous work, and unpaid ground rent or service charge arrears on a lease can all surface late in a purchase — particularly in an auction legal pack, which is exactly why a solicitor needs to review it before you bid, not after you've won the lot.
Occupancy issues
Sitting tenants with strong statutory protection, squatters, or unclear vacant possession can all delay or complicate a purchase well beyond the price you agreed. Confirm vacant possession, or a clear timeline to it, before treating a discount as real.
The rule of thumb
If a discount looks too large for the property's apparent condition, assume there's a specific reason you haven't found yet — and go find it, rather than assuming you've simply found a bargain nobody else noticed.