Out of interest, how many of them do you own, what type are they and how did you acquire them?
bought a large house in the west end (best part of the city) way back when for peanuts, they also bought 3-4 fields for peanuts too on the other side of the country for initially business use for 10 years then for residential housing.
The home went up in value by over 10 times what was paid for it over a period of 30 years. The land even more so when it got planning permission to build over 100 houses on it, still own the land but because its a valuable asset you can get equity against it. the home was remortgaged freeing up equity to buy 10-13 houses in a not so nice area from the equity freed up just from the home alone. It's not the scummiest place but I wouldn't want to live there personally. As an example imagine buying somewhere in London 35 years ago for 100k and it being worth £1.5 million today. You could free up £1 million in equity and buy 10 * 120k flats say in Manchester or something to rent out with 20k mortgage each. This is just a simple example.
The commercial properties were initially ran as the family business. So they were the bread and butter. Bought several along the way and then eventually just rented them out.
Right now I'd say buy to let is dead. You don't get any of the breaks you used to get before. In terms of you could offset mortgage interest payments against tax paid, etc. you don't get any of those as well as increases in SDLT they have hit buy to let very hard.
i'd still say property is a good investment but it's nowhere near as lucrative as it was previously unless you happen to pick the right area in which property values continue to soar.
commercial property again can be a minefield. lets say you buy a corner shop and lease it out for 25 years at £25K per year. if an aldi opens up 5 mins away you will lose hard. so the risks are far greater these days as the big boys have a lot of clout and are constantly expanding into smaller areas now to increase their market share.
Things are certainly harder now.
Which is why it's now likely impossible to replicate the above.
Which is why people who are getting in on it now don't make that much unless they have a lot of cash lying about. It's why foreign investors are buying everything up in the UK. They have bundles of cash and can take the risks.