If you are in the Liverpool area, an excursion to Birkenhead is a must: It grew rapidly in the 19th century as an extension of Liverpool in the industrial revolution and was connected to Liverpool in 1886 by the Mersey railway tunnel, the most ambitious tunnel project of the age and you can still admire its splendid ventilation towers on both sides of the river. This could be a good nomination by itself. 

The wealth of the town is especially obvious around Hamilton square with one of the highest concentration of protected buildings in the UK. The classical town hall could stand in much larger cities. The check board street pattern is reminiscent of Edinburghs New Town. A visit to Birkenhead Park is pleasurable and even impressive but in a country with the greatest gardens in the world (besides Japan perhaps) it has too much competition to stick out. But it is well known that Frederick Law Olmsted, the architect of New York's  famous Central Park was greatly impressed and inspired by Joseph Paxtons Design. How about a double nomination of the world's first publicly funded park and England as an inspiration for Americas most famous Park. The latter would make an excellent WHS all alone! 

Just next to Birkenhead is another, even hotter candidate for WH status: Port Sunlight is a wonderful victorian factory village. The houses are by several well-known architects and I would gladly live in any of them! I had even the pleasure last summer of staying for one night in one of them that was used as a B&B! The most unbelievable part is Lady Levers Gallery, a splendid building with a collection that includes Pre-Raphaelites and  even a turner. The great man, the director of the soap factory, thought his employees should not only have leisure time and nice homes but also access to beauty and art. Even with Liverpool having lost his WH status and Manchester actively preventing its own nomination there can be no doubt that his industrial belt was the most innovative region in the world for several decades.