There are few enough diamonds in the rough on Sydney Avenue, one of the most desirable roads in Blackrock, Co Dublin, as most of the lovely grandes dames have already been refurbished.

Number 20, which has been in the same family since 1955, retains all its period details since it was built in 1880. High ceilings, coving, period fireplaces and the quirky Gothic windows in a bedroom on the return are notable.

And the light-filled property, which extends to 176sq m (1,894sq ft) has a few surprises up its Victorian sleeves. The rear garden – which has a south westerly orientation – extends to a very generous 170ft in length. In addition, there is vehicular access to the rear and the original coach house still stands.

This coach house could be transformed into a 130sq m (1,400sq ft) two-bedroom unit. Though planning is required, it should be straightforward enough as there is precedent in a number of properties along the road. "For a high-end two-bedroom coach house mews, rental income should generate in the region of €3,000 a month," according to Ronan O'Hara of Sherry FitzGerald, who is handling the sale.

In terms of value, should new owners wish to sell off the mews when converted O’Hara estimates it could generate in the region of €875,000 to €900,000. Should the property be sold off, the main house itself would still retain an 80ft garden.

However, with the current trends, new owners with deep enough pockets could also transform the coach house into a stunning home office or guest lodging and still have a fine five-bedroom period house to the front. While renovation is required, the roof was replaced in 2013, so that will be at least one item removed from the renovation list.

Number 20 Sydney Avenue, which is Ber-exempt, is on the market through Sherry FitzGerald seeking €1.295 million.