No. The requirement to make adjustments falls on the person offering the service, effectively the business owner. You can find more information about this in the equality act itself or in the Equality and Human Rights Commission code of practice for service providers.
If it is under 0.5cm then it could be too small to need a ramp, but anything over that needs either a slanted edge or a ramp to be considered level access. The equality act doesn't specify when you might need a ramp, but it does say that disabled people should be able to access shops, businesses and public functions on an equal basis with non disabled people.
That's because people who can't use your shops are just shopping elsewhere - mostly in the high street chains in the other part of town.
Unfortunately that doesn't mean all wheelchair users can. There are often big differences between people that use manual wheelchairs and those that use powered wheelchairs. There are also differences between people that use different kinds of powered wheelchairs.
Not without their consent - and if you do you risk injury to yourself, them and anyone else helping. Wheelchairs understandably vary in weight, but including the person in them can come in at over 200kg. That isn't a safe weight to lift.
Yes, there are. Isn't it outrageous, 22 years after the law on reasonable adjustments to goods and services, that so many places don't have level access?
Actually, it does. The equality act applies to all service providers, and that means anyone selling things to the public - be that goods or services.