With regard to Poland, yes, when hundreds of thousands headed west (not just the UK), Polish university graduates were able to find all the lesser-desired jobs, washing pots and turning down beds in hotels/restaurants for wages that were to them astronomical. At the same time, hundreds of thousands from Ukraine went to Poland illegally, filling the created void. - Everyone goes west; it's where the money is. Since we have left the EU, the Poles were allowed to stay, but as this country slips deeper into the doldrums, at the same time, Poland is on the rise and rising fast. Hundreds of thousands of Poles have been flooding back home, and there is a clear divide: those who have only managed to find such low-paid jobs are the ones going back, whereas those who have done better tend to stay. Personally I have not come across any large-scale resentment to what must be since the war, around 2 million Ukrainians in Poland, but to be fair, I know fewer Poles now than I used to. Hosting the Ukrainians by the Poles is a strong statement of being anti-Russian, and the Ukrainians are working, contributing and helping the Polish economy, which has now reached a trillion-dollar turnover.
Back to the other point, I am sorry; I just cannot imagine Ferage wanting to take power and then abolish democracy. You could equally throw the same suggestion at Corbyn or Polanski, both leaders of, in my view, equally out-of-the-ordinary??, untried and tested parties. Just as Labour has done from the Tories, whoever takes power next is going to inherit all of the problems Labour did and maybe some that Labour will have since created. So, any of three new parties could say, 'We have not had enough time to sort out previous problems or time to implement our plan, so we are cancelling the next election!!' I just cannot imagine the nation allowing such a takeover.
I will agree with your comment; it is not a good idea to ban or refuse debate. Personally, I am not a fan of banning any political party. Never really understood the "ban the BNP" philosophy. If you ban it, you just drive it underground; you can make it more, not less, attractive to people with extremist views. When a radical party or movement is out in the open, you can keep an eye on it, and yes, let it show its inadequacies as a serious alternative – extreme left or right. In Poland they have recently banned the Communist Party. Admittedly, it's more to do with always distancing themselves from anything Russian and the shackles of the decades of being a semi-occupied Russian satellite state, but it's an ideology that stands no chance in modern Poland and has now just been given that air of mystery, maybe mystique, to anyone who wants to find out more about it.