A pressure reading taken while nothing is running does not tell the whole story. The useful assessment combines static pressure, pressure during use and available flow, then relates those readings to the outlets you want to operate together.
We look at where the problem occurs: one shower, hot water only, the entire flat or several properties sharing a supply. Existing valves, filters, pipework and hot-water equipment can affect the result. If performance has suddenly changed, the cause needs investigating rather than assuming the original installation needs a larger pump.
A reading at the building entrance is not a substitute for understanding conditions at your flat. Where demand varies, measurements at a relevant busy period or further investigation may be needed.
For the distinction between a weak supply and a local restriction, see our guide to water pressure and flow problems.