Mirko,
It is very difficult for people to give a net figure, because it varies from person to person and depends on things such as their own personal tax code (the amount of salary allowed free of tax.) The amount of additional income they may receive, and the proportion of that income that is taxable. Pension contributions they may make, that are usually not included in the taxable element of their salary, and they will vary from person to person.
However with a very broad brush:
Using the figure you have mentioned of £ 46,884 gross
A normal UK tax allowance would be £6,475 (the amount you can earn before tax is payable.) The tax would then be £8,683.60 and the National insurance would be £ 4,248.44. This gives a total deduction of £ £12,912.04 leaving a net wage of £ 33,971.96 or £2,831.00 per month
This figure doesn't allow for additional deductions (pension, subscriptions, etc) nor does it allow for additional tax concessions such as FREA (fixed rate expenses allowance.) But it should give you a rough idea.