What sort of info are you looking for, have you found the horse you want and wonder about castration? or are you still looking?
You can castrate at any age and there will invariably be a change in temperament, the real extent depends on the horse, nowhere else in europe geld there horses as a matter of course its only us ridiculous english, spanish horses especially (altho arguably most horses if only people would give them a chance) are very well mannered with everything in tact (as nature intended)
If you haven't found the horse you're looking for (Im not sure if I'm allowed to put organizations up on here, if its spamming or not) pM me and id be more than happy to recommend some great organizations who could help you find the perfect horse.
I've had numerous Spanish horses, from home bred foals taking there first steps to humungous testosterone fueled beasts, there's no real difference! Awesome horses!!!
I bought my pre, previously known as andalusian from Spain in 2009. He is entire and I worried a bit about it. What can I say. These horses are Just the most amazing horses, happy, willing, beautiful, so easy to train, and his manners are impeccable. My stallion is on a large livery yard with mares and geldings and at times other stallions and had no problems at all. People who don't know him don't realise he is a stallion! The Spanish love their horses but don't Molly coddle them like we do, they are at best firm but fair! I bought mine independently as I saw him advertised. To get a good idea of prices, do a search on Spanish sites type in caballos vende or use Google translator and spend time having a look so you can get a good idea of what you should be paying and if you use an agent, how much more they are adding on top! I got my horse of a lifetime this way and I will do exactly the same when I can afford a second one! Good luck.
Not too sure what info you want. Do you have facilities to keep a stallion? You may find that most livery yards are unable to accept a stallion so it may be a bit more difficult finding a stable for him and turnout may be a challenge due to lack of suitable fencing.
You may also need to be very careful about the change in diet, many Spanish horses (south of Spain) are not used to the kind of grass you get in the UK and you may need to take it very slowly with any changes. The weather may also make a big difference in temperament, many horses are more chilled in the heat of Spain and more lively in the wind/rain of the UK.
bwpre: sorry to disagree, but most colts are gelded here in France unless they are intended for breeding. Granted there is a bit of indiscriminate breeding so more stallions sitting around not doing much, but the majority of male horses are geldings. The few horses there are in Greece are almost all geldings or mares and as far as I know the Germans are rather strict about gelding males that are unsuitable as stallions, so no it's not just the British that geld!
You really need to think about what you want to do with him. Quite often horses are called Andalusians but they are not purebred, or not registered. If he is purebred and registered he will be a PRE. If you know his name and numerals then you can check if he is registered on www.lgancce.com .You need to select Arbol genealogico PRE, click on the UK flag(top right)and enter his name and numerals in the name of horse. If his details come up with a little arrow beside it, then click on the arrow and that will bring his pedigree up. If there is a 'B' next to 'Estado reproductivo' on the top of his pedigree, he is graded for breeding.
If you get NO EXISTEN REGISTROS CON ESOS FILTROS. Then he is not registered or graded.