James Salt scored five as the London side beat Portobello 13-6. Watford also defeated Scottish opposition but left it late to clinch a 12-11 success against Caledonia.
Caledonia led 10-9 after three periods, but then two goals by Finlay Parnell and a Tom Kelly strike put Watford in charge before James Miller scored a man-up goal for Caledonia near the end.
Sheffield, yet to play either Penguin or Watford, easily defeated Exeter 21-9 at the new Eton College pool.
City of Bristol took maximum points from their two games - a 16-10 defeat of Lancaster, then an 18-17 victory over Exeter.
In men's Championship 2, Sedgefield extended their 100 per cent record with a 20-10 victory over Otter.
Photos - Above (by Trevor Hyde), Dan Atkinson scores one of his eight goals for Sheffield against Exeter. Below: A view of the new Eton College pool, which BWPL are using for the first time.