About 10 years ago, I took over running a bar with a friend, and had several catering otions we could go down, as the place had a full kitchen, albeit with v. old equipment.
One of the reps from one of the large catering companies came for a meeting, and told us all we needed to produce an extensive menu was a bank of high speed microwaves, a couple of toasters and a couple of deep fat fryers. There is no end to the items you can buy prepacked/cooked. Even poached eggs could be delivered vacuum packed (yuk)and then whacked in the microwave. You didn't even have to think about timings as each product came with a coloured sticker, and you just pressed the said colour button on the control panel.
They could even supply china for you to plonk the frozen pies in, they were a perfect fit, and the last minutes of cooking involved a blast for the inbuilt convector to brown/crisp them. The rep said that if a touch of sauce leaked from the pie onto the china, don't wipe it away, as it gave the illusion of it being 'home-cooked'.
So if someone came in and ordered pie, chips and peas, you would wack the pie in one oven, the sachet of peas in another, and a sachet of chips in the deep fat fryer.
I now work in a different career, and my office in central London looks over a busy 'eating' street. When I'm in work early at 7.30 or so I see all the catering companies delivering to the major chains, and pubs advertising 'home cooked' food.
Word of advice for anyone visiting central London, don't automatically go for one of the chains. Like a lot of us looking in Lidls/Aldi our brains are pre programmed to look for brands we know. Don't dismiss or look over little restaurants, even if the front may look a little jaded, and there is not an expanse of sparkly plate glass (i.e the chains)
If they are surviving in an area awash with chains, then the likelehood is that they are a favourite with locals.
I'm often stopped in the street to ask where the nearest Pizza Express is - I always point people in the direction of the local Italian. They have been there 40 years and cannot be beaten. Independents are more often than not run by the owners, who actually care that customers come back. They have a stake in a business and often have family working there. Unlike managers in a chain, who despite taking a pride in their work, ultimately have no stake in the future health of the establishment, so may not be quite so customer driven.
And if anyone would like recommendations for fab restuarants in Soho, London W1, please message me. There are plenty of hidden gems at the same price or less than the chains, and the food is normally divine.