The Stamp Duty Mistake Costing Buyers Thousands

Think you paid the right Stamp Duty when you bought your city pad? Think again.

According to property tax specialists SCA Tax, thousands of modern homebuyers are unknowingly overpaying — simply because their sleek, lifestyle-friendly apartment includes commercial features that make it eligible for tax relief.

An audit of over 7,000 transactions by SCA Tax found that 1 in 9 buyers (11%) had paid too much, missing out on refunds worth an average of £13,000.

Stamp Duty Land Tax (SDLT) is the tax paid when buying property in England or Northern Ireland. As of April 2025, most residential buyers pay:

• 0% on the first £125,000
• 2% on the next £125,000
• 5% on the portion from £250,001 to £925,000

So, a £295,000 apartment would typically cost £4,750 in SDLT — unless there’s more to the building than meets the eye.

“People assume that if they’re buying a home, they must be paying residential rates,” says Sean Swimby, Director and Founder of SCA Tax. “But today’s city-centre developments are built for modern lifestyles — with cafés, gyms, salons and co-working spaces all under one roof. If even part of your block is commercial, it could mean the whole property qualifies for lower non-residential tax rates.”

And here’s the surprising part: you don’t need to own the coffee shop, gym or office space beneath your flat. If it’s part of the title, or part of the building acquired in the transaction, it may be enough to trigger “mixed-use” status — and unlock thousands in tax relief.

SCA recently helped buyers of a block of flats in Manchester, part of an aparthotel-style development, recover a significant SDLT refund after the property was wrongly taxed as fully residential.

“It doesn’t need to be a live/work unit or anything connected internally,” adds Sean. “We’re seeing more and more people move into buildings with built-in cafés, yoga studios, or even ground-floor retail — and they have no idea they could be paying thousands more than necessary.”

But most people miss out. That’s because HMRC’s SDLT calculator doesn’t factor in these reliefs, and conveyancers rarely advise on tax — leaving buyers to assume the amount they paid was correct.

“The rules around Stamp Duty reliefs are incredibly complicated — even for professionals,” says Sean. “We regularly see stylish, multi-functional developments wrongly taxed as standard homes — and most buyers only find out when it’s too late. That’s why it pays to get an expert review.”

In one recent case, a homeowner reclaimed £8,500 after their flat above a commercial premises was misclassified. SCA’s data also showed:

• 69% of overpayment cases involved probate sales
• 20% involved mixed-use properties
• 6% were linked to the 3% second home surcharge
• The average refund across all cases was £12,909

And it’s not just homeowners missing out. Sean warns that developers, investors, and even employers can also benefit from little-known reliefs in situations such as:

• Buying from an estate (probate purchases)
• Stepping in to rescue a broken chain
• Acquiring a home to help an employee relocate
• Purchasing multiple dwellings or new-build units in one transaction

“We often see even bigger overpayments in commercial transactions — especially where the seller’s circumstances trigger overlooked reliefs,” Sean explains. “In some cases, SDLT can be significantly reduced — or even wiped out completely.”

Still, the system remains deeply flawed.

“In an ideal world, HMRC urgently updates its SDLT calculator to reflect the real-world complexity of property purchases, the government simplifies the rules around reliefs, and there’s a safety net to protect buyers,” says Sean.

“Until then, if you’ve bought a property in the last four years — and it wasn’t a plain vanilla house — there’s a strong chance you’ve overpaid. It’s worth speaking to a specialist about what can be done to put it right.”

SCA Tax offers Stamp Duty Rate Certificates to help reduce the risk of incorrect Stamp Duty Land Tax (SDLT) assessments during property transactions.

The certificates provide formal assurance that the SDLT has been correctly calculated by a specialist tax adviser, rather than relying solely on the assessment of a solicitor or conveyancer, who may not have the same level of tax expertise.

By using SCA Tax’s service, the stamp duty calculation is backed by the firm’s professional indemnity insurance, offering an additional layer of protection and peace of mind for buyers, solicitors, and conveyancers alike.

The move is designed to support professionals and property purchasers in navigating the often complex SDLT rules, particularly where multiple dwellings relief, mixed-use status, or non-standard transactions may apply.