Should Halfords replace my faulty four-year-old bicycle?

The bike was never right from day one and now the cost of getting it repaired will be more than I paid for itI bought a bike from Halfords’ Edinburgh Hermiston Gait store four years ago and no longer have proof of purchase. But from day one the bike was never right and I believe it was never assembled properly – the handlebars kept coming loose, for example. About a year after buying it I took it back into to Halfords, but even after that it still wasn’t right and I now realise