“Size! That’s what brought us here.” Alex Bewg, the new and somewhat startled owner of a rare and historic inner west property was clear on why she is moving her family from their comfortable home in Forest Lodge to a near-derelict building in Newtown.

Despite heritage restrictions and flight-path noise, Ms Bewg and her husband James Hebron were keen to snap up St Bede’s Convent at 26 Oxford Street. They paid $2.5 million at auction for the two-storey building on a 495-square-metre block.

The historic estate was one of about 500 properties scheduled for auction in Sydney on Saturday. By early evening Domain Group data had collected 372 results showing a clearance rate of 73.7 per cent.

Domain Group’s chief economist Dr Andrew Wilson said it was another heartening result for sellers. “The Easter break has made no change to the market,” he said.

There were three parties who registered to bid following the five-week marketing campaign that saw 69 groups inspect and 23 contracts issued.

Size! That’s what brought us here.New owner of St Bede’s Convent, Alex Bewg.

The couple calmly but confidently bid against another family while a third party, an investor, was struck with cold feet after assessing the restoration project’s enormity.

The heritage building has seven bedrooms, two bathrooms and dual-street access for two car spaces.

A crowd of 40 watched as the first bid of $1.6 million was rejected by Di Jones auctioneer Gavin Croft, who joked that optimism was alive and well. He soon swallowed his words and accepted that offer followed swiftly by Ms Bewg’s $1.8 million bid that kick-started a bidding war between two families.

After nearly snaffling the property at $2 million the underbidders offered a further $100,000 and repeated their tactic with a $2.4 million bid and another $20,000. Ms Bewg sealed the deal with a further $80,000.

“We didn’t think we’d get it,” said a bewildered Ms Bewg. “We thought it would have gone much higher than it did.”

“We’ve been looking for a year to buy a warehouse and these [heritage] restrictions mean a lot more work but we like the heritage style,” she added.

“We now have to break the news to our three teenage sons that they won’t have an en suite.”

Elodie Fabre​ of Di Jones Real Estate Woollahra said she was happy with the result, though declined to reveal the reserve price. She added that the sale price would have been higher if the certificate of occupancy and certificate of title were in place.

“The buyers’ feedback of $2.3 million and the result reflected the heritage restrictions and work needing to be done before you can move in,” she said.

The freestanding residence was originally named Prospect Cottage. It was built in 1857 before being updated with Gothic Revival and Victorian Italianate additions.

It had once belonged to the Richardson & Wrench co-founder, Robert Richardson. In 1883 it became St Bede’s Convent. A vestry and chapel have since been repurposed as a living room.

Speaking on the behalf of the vendor, school board member Tarne Dirou​, of The Athena School next door, said the school recently decided to subdivide so the heritage home could be restored by a family.

“It was predominantly used as a residence for our principal and her family, and lately a couple of rooms [were] used as classrooms,” Ms Dirou said.

“It’s sad to see it go but the money will go back into the school to pay off the mortgage, pave the playground, buy more play equipment and maybe even a school bus.”