We used Currencies Direct when we bought our place. At the time they appeared to offer the best rates for the larger transfer
However, for our normal transfers to top up our Spanish account we now use Wise (who weren't around when we bought our property). We find them very competitive, very fast as money in the designated account within minutes, they allow you to transfer exact amounts so no charges deducted if you are paying for work done and the rates are real time so fluctuate as the market moves which is why they are competitive