Yes, that picture shows a typical UK installation. But it's not typical the world over. I come from a small back-water country (US) where things are rather different.

The picture shows a typical "meter base". Power comes from the utility either above ground or below ground via a metal conduit to the meter box. There is no accessible circuit breaker/fuse on the input side of the meter. The meter is secured into the meter base with a metal band, which has either a tamper tag or padlock (if your reputation dictates), which must be cut to allow the meter to be removed. Unplugged more precisely, which bridges the contacts between power company and house. Wires in the meter base usually have no slack.

From the meter base, wires go the the breaker panel either directly behind through the wall or through metal conduit.

Perhaps the fact that you're not knowledgeable in the power system many users pf this forum have and any attempt to follow your suggested advice could go horribly wrong, suggesting actions on line power installations is not wise.

Your post also suggests running neutral wires "through a CT", which many people would take to mean "disconnect the neutral" which could be fatal if there is any load.

 

Well, at least I clarified the current transformer connection. My suggestion was rather safer that the preceding post, which was made by a US resident.
Even meters installed in Britain in the 60s have four wire in a line with two neutrals together in the middle.
I thought our meter was a bit primitive! The power companies are trying to get everyone on to the "smart" meters. Only, they weren't that smart, because the first generation all gave up the moment someone changed supplier.
As they were designed by GCHQ, I can guess what the government had in mind. . . .

 

Really, all that is needed is to completely disconnect the external load and note the change in meter reading over some time period. that will show the power use charged to the account. And since the disconnect is beyond the meter there does not need to be any entry to the meter box.
And an interesting thing is that I have had to enter my meter box several times, breaking the seal each time, and never had any comment of any sort from any of the folks from the power provider. Those included replacing the cable from the drop line to the box and adding a connection for the central AC compressor unit.