A couple of countries missing here. Venezuela and Paraguay in South America, Tanu Tuva in Asia. You need to add in some dominions (Australia, New Zealand and South Africa). These countries declared war independently of the UK (indeed South Africa nearly remained neutral). If you count Canada as a country then you have to also count these three. Egypt and Morocco are debatable. Morocco had no foreign policy independent of France and if you do not count Aus, NZ and SA as countries you cannot count Morocco as a country. Egypt was nominally independent but fully controlled by the UK, again you cannot say it was independent if you say Aus, NZ and SA were not independent.