My new bike came with an aliante. Tried it and knew in 30 mins it was not for me.
Now I have an SMP (glider model, pricey) and I would recommend you to get one. There are lots of models in a wide price range.

Mine seems too narrow (136mm) for my sit bones (round 140) - but it is perfect, so I don't buy the sitbone width thing.

Try finding a UK place online with an exchange policy.