Theres a lot of variables ... thats why people dont answer these ' which machine ' threads
variables include ... are many of your EOTs up a stairs ..like without a lift
How strong and fit are u ... to carry or haul which machine
Do your EOTs usually have a good supply of hot water ... if not a water heater is usefull but usually an extra cost
I think your 1500 (+vat ? ) is a bit on the low side ... allow 2000 to 2500 and you have more choice and more pump pressure and vacuum strength .
Il pick one ramdom one on the lower side of the scale ... Airflex miniflex ( built with 300psi pump , 1200w+1400w motors is about 1600 ... then u need hoses wand etc
There are better miniflex options for a bit more money , im picking the miniflex because u have a better chance of hauling up a stairs than a full size machine ... if you can handle a full size machine , go for it . Airflex , enforcer etc
You still have no water heater ... look at an external inline heater as the heater adds weight to the machine you have to haul .... unless its an immersion heater which weighs not a lot . (available on alltec ,ashbys machine)
If your EOTs are typical and not high end , get a used rotary scrubber ...about 200rpm or thereabouts ... and a medium hard bursh , and perhaps a softer brush also for delicate carpets ... prescrubbing with the rotary and a good detergent cound be the single biggest timesaver .... before you wash it with your machine .