Just make sure you find out exactly what services they are providing for the price - the fixed-price options can look cheap, but if they are not including some essential services in the price (e.g. planning searches, boundary searches) it could cost more in the long term, and you will have to deal with more people also.
Find out also how they will be closing the sale, i.e. by post or in person, as if by post they will draw down a full week ahead of closing, which will cost you in interest, and might be troublesome if you want a quick closure. They may charge extra if you need them to do face to face close.
Just some things that came up when I used another fixed price solicitor in East Cork, I'm no expert. I found also that the fixed price did what it said on the tin, but offered no advice on anything, which from speaking to other people who were buying 'full-price' solicitor would.
Per the Key Posts, what looks the cheapest isn't always the cheapest or the best option.