Some are doing it to the exclusion of representing the consumer home buyer.  

Dining rooms are a complete waste of space and are typically used to store stacks of news papers and old computers that don't work.

ROE is so low (.6%) that at this point in our RE journey, we believe our $$ can do more for us elsewhere and we still sit within Sec121 exclusion to avoid some CG tax. 

Overwhelmingly Positive Testimonials and Reviews from StudentsThe "reviews" for a guru come exclusively or overwhelmingly from individuals who create accounts on BiggerPockets with seemingly no other purpose than to dispense undying love and/or personal loyalty to the guru, with lengthy commentary about the complete life turnaround that spending $5K - $100K had in a very brief period of time, rather than a rational assessment of the pros and cons of the program and their outcomes achieved so far.  

Even with a exclusion of gain under Section 121 (MFJ: $500k), they are looking at over $100k in taxes from a sale.

I like having one account exclusively for rent payments and another for security deposits.

Is this market accessible for the average investor in the UK, or is it exclusively banks and hedge funds who buy/sell these sorts of instruments?

Get to go slow and learn over time, build capital, and qualify for the primary res cap gain exclusion. 

I am a bit skeptical with these newspaper lists. 

No one in the area has been successful, they even put an article in the local newspaper saying that they haven’t changed anyone’s property tax that has appealed.