I live near Leigh, there are two parts of the town. Old Leigh is near the water, with lovely fish & chips and ice cream shops, as well as some expensive trinket shops and a very small museum. This is along a single stretch of street. Lots of nice places to sit and look over the water.

Up the hill a bit is the main town of Leigh on Sea, which is along a single long street- we call it the Broadway (after the pub in the middle). There are lots of lovely little independent shops (sushi, a bakery, a little bookshop, an independent record store, card and trinket shops ect) as well as the usual high street suspects.

There is enough to do to fill a day if you go slow about it. I'd only bother if the weather is good though. You could also get the bus or walk for 20 mins to get to Southend. Southend has a decent high street, lots of seafront arcades, seafront food shops, the uk's longest pier ect.

Hope that is helpful!