Radio region help needed

Hi

I am hoping someone will be able to help me. I am currently looking to buy a new smartphone, Samsung Galaxy Grand Prime SM-G531H/DL. It is the unlocked version. I do not have a huge budget or choice, I live in Guatemala right now, but will soon be moving back to Europe. I currently have a Samsung pocket neo which is very frustrating, so slow, hangs so bad i can't even answer calls, hence the desire to replace it! As this purchase represents quite an investment for me I want to get it right. The guys in the shops are helpful, but much of what I ask is outside their knowledge or experience. I want to make sure that the phone I buy will be usable in Europe. I have done some research into radio bands, but I would like some confirmation or advice. So, the phone uses 850/900/1900/2100. Guatemala's Tigo uses 850 for both GSM and UMTS. Bulgaria uses 900/1800 for gsm and 900/2100 for umts. UK uses 900/1800 for gsm and 900/2100 for umts. On the face of things it looks like the phone should work in Europe, but am I missing something? If it doesn't work there, is it possible to covert it by something like flashing the radio? Also just in case anyone knows, does that model come with lollipop as standard? All these questions seem simple, but unfortunately here you don't always know until you get it out of the box and then it is too late!

Many thanks