Profit Margins and expenses – there’s easier ways to earn a crust?

When looking for a comparison of typical Private Rental Costs v Income I struggled. The Tax return asks for number of properties [SA105 box 1], Income from rent & property [box 20],

They ask for Expenses-
rent, rates, insurance, ground rent [24]
repairs & maintenance [25]
allowable finance costs [26]
legal, management, professional [27]

Less private use adjustment [30]

Taxable profit [40]

The profit margin (for our own interest) requires an estimate of the portfolio value.

Has anyone seen this information published?

20/21 will not be typical for many due to the pandemic. Having done this for the last two years I got:-
Box no. 19/20 20/21
24. 6% 8.5% (insurance etc)
25. 7% 12.5% (maintenance)
27. 4% 4.8% (professional)
30. – 3% – 4.1% (private use)
40 86% 78.3% (taxable profit)
ROCE 5.25% 3.9% (before finance cost)
Net profit 2.25%. 0.9%. after finance cost.

Then of course there’s tax on the profit [40], and loss of certain benefits as income increases ……..
One thing is certain, there’s easier ways to earn a crust!

Chris