In general the wattage of appliances is dropping as there's less demand for short, high temperature boil washes more than anything else due to advances in detergent and changes in how people wash laundry that have been going on since the 1970s.
The advent of heat pump dryers has also dramatically dropped the power consumption of laundry appliances.
A lot of older machines here would have pushed up to about 2.9kW. Also it's worth noting that the UK historically used 240V and the rest of Europe (including Ireland) used 220V. They've harmonised to 230V as part of an EU and also IEC (global) harmonisation that's been going on since the 1990s.
But, a resistance element will actually consume more energy and run hotter at higher voltage. So, if you drop the voltage from 240 to 220, your heat output actually drops accordingly. So there's a little bit of vacation depending on the actual voltage that you're receiving at your house. It should be close to 230V these days, but you'd get old supplies that could be rated for 220V +/- 5% or UK supplies that could be closer to 250V some of the time.
Typically as transformers were replaced at network level, they adjusted the systemwide voltages to hit closer to 230V.
You'd actually have no issue here running a washing machine and dryer simultaneously on a single circuit. The minimum radial branch circuit is typically 20 Amps and ring circuits deliver 32 Amps.
Our systems are a little bit different to those used on in continental Europe, Australia and in the US in the sense that the power is distributed on a high amperage circuit to the outlets, but the plugs themselves carry a fuse (maximum 13amps, and often 3amps or 10 amps in lighter appliances). So the last line of overcorrect protection here is actually in the plug top itself.
There's an image of my Miele TwinDos W1 and T1 Dryer (heat pump).
2 plugs with 13amp fuses, plugged into a dedicated radial circuit with an RCBO rated at 20amps.
The second photo is an illustration of how the fuses work.
