whether they will be imports that may need special wiring etc.
The washers and dryers sold here are not the exact same models as in North America.
American dryers are fitted with 60Hz motors and have wiring which is designed to work with the standard dual-voltage U.S. residential supply (your dryer outlet in the States actually provides
both 120
and 240 volts simultaneously).
The U.K. versions are wired for 240V-only supplies and come with 50Hz motors so that there's no incompatibility in that regard, but as Cabbage said it's the power drawn by these larger dryers which is the problem.
The standard U.K. 13-amp outlet is good for appliances up to around 3kW. The Maytag Atlanta dryer, to take one example, is rated around 5kW, which means that it will draw approx. 22 amps, hence the need for a dedicated 30A circuit.
If there happens to be an old, unused cooker (range) or shower circuit which can be diverted to the dryer position that would most likely be satisfactory, but otherwise would mean running a new dedicated circuit right back to the distribution panel. If there are no spaces in the existing panel, you'd have to add to or replace it. Price would obviously depend upon what's there, how far away, ease of wiring, etc.