Weights and measures is one of those areas where giving people a choice is a bad idea. Trying to run two systems at the same time leads to confusion and error. In the NHS at least two people have died because they have been given an incorrect dose due to a conversion error. One was a newborn who died of an overdose of a drug and the other was a teenage cancer patient given too much radiation. An airliner ran out of fuel because the pilot thought he had 22 000 kg of fuel when he only had 22 000 pounds.
The UK started its metrication programme in 1965, with an intended finish date of 1975. The UK government was happy to agree to metrication as part of its entry to the European Community as this was already government policy. The 1981 EU directive required the UK to produce metrication legislation itself, which was duly passed by Westminster. So, the EU did not ban us from using Imperial units - that was done by our own elected MPs (for good reason).
Your baby was weighed in kg for the NHS records but it was reported to you in Imperial. Someone was trying to be helpful. The fact that our road signs are still Imperial is a disgrace and it has consequences. Foreign lorry drivers, unfamiliar with Imperial, have been hitting low bridges for years and it is only recently that bridges have been dual-marked. Foreign vehicles have no requirement to have dual-marked speedometers and unless we plan to cease all foreign trade this will lead to accidents.