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Notes in italics are from London 1: The City of London  by Simon Bradley and Nikolaus Pevsner (1997)
Yale University Press, New Haven and London

Facing King Street, the newly made processional route to Guildhall, Wren provided a spectacular E front. Four attached Corinthian columns on a podium carry a pediment set against a big attic storey. The flanking bays have Corinthian pilasters at the corners and eloquent arched niches in round-headed surrounds. Similar niche in the centre bay, with large arched windows in the bays to either side. The impost mouldings run across the front between the columns and all five bays have rich carved festoons above.
The side towards Gresham Street Street is also treated as a facade: five arched windows in the centre, flanked by straight-headed entrances with circular windows above, the bays unevenly spaced. In the attic small segment-headed windows.
The W tower has tall obelisk pinnacles and a balustraded parapet. The bell-chamber below has on each face a round-headed opening in a shallow square-headed recess. The restored spire, of glass fibre, faithfully reproduces the four pedimented faces and octagonal spirelet of its leaded predecessor. ... 
Quoined W front, far more modest than the E ... (not shown here; picture at external site). The plainer treatment here and on the rubble-faced N front (shown at the top) is explained by their original setting facing narrow lanes. The W front is not square with the N and S sides ...
The interior (not shown here) is particularly spacious but was never of exceptional architectural interest. ...
Brown restored St Lawrence as a Guild church to provide a setting for Guildhall ceremonies ...