There are a number of ways of getting Euros, it’s not quite as simple as when you go on holiday and get cash from the local exchange bureau, but its not complicated.
One way is to discuss with your UK bank, they will be more than happy to work with you and arrange to take money from your account convert it to Euros and deposit it to an nominated Euro account (e.g. the Agent or Lawyer) but the bank will charge you a fairly hefty commission and their conversion rates are not brilliant.
Another way is to open a UK Euro bank account and transfer from your Sterling to Euro Account, but again your bank will charge, I don’t know the amount, as I didn’t go down that route.
I had heard, I can’t remember from where, it may have been a colleague at work it maybe from the Internet, about currency exchange companies. I think one place I had read these was both on Gekkoportugal and PPProperties websites. I am sure the companies they promote are fine but I focused on two that I found, Worldfirst and Moneycorp, they both offered online service and their exchange rates where much better than the bank or Post Office, they both charged a small fixed rate charge, but at the time Worldfirst offered your first transaction free, e.g. no admin charges and if you transacted over £5000 its was free anyway. Moneycorp charged whatever, it was only a very small charge, but a charge the same, but they did offer a privilege card that you could use at the airports to get commission free currency at preferential rates. It was all on line and quite easy to open an account so I did both.
For our first transaction to pay the deposit we went with Worldfirst, just because it was cheaper. The first transaction did take a few days, just because I didn’t have the money in the bank, it was in various savings accounts and so we needed to get into our main bank account, but once organized the transfer was done in a couple of days (later transactions have been processed in a matter of hours) The first thing is to tell the currency exchange company how much you want in either £ or € and they will quote you a price (exchange rate) as long as you are happy they will then fix the purchase for a period, send you an email with all the details of the transaction and give you their account details to transfer the money into. You can do this with your bank and they usually don’t charge, if you have Internet access to manage you account you can do this yourself. Then you have to give details to exchange company of the account you want to transfer the money to e.g. the lawyer or the agent, they will be able to give you the details of their account. You will need their IBAN account number, Bank Swift Code, Bank Name, and the Name on the account. Once that’s all in place, its done. Just get the agent or lawyer to let you know when the money is in their account.