Crossword Puzzle - August 2013

Welcome to the crossword puzzle for August 2013! Can you believe that it's been a month already?

As per usual (or if you're new here), the answers to the puzzle below will be posted next week Tuesday, 3 September 2013. If you'd like to be mentioned in that post, then play the game! Print the crossword out, or scribble on it electronically, and submit your answers (either the completed image, or just a list of question numbers and answers) to me via either Twitter mention or a message on my Facebook Page. Do not enter your answers in the comments below, or punch them onto my Facebook wall: you'll spoil the fun for everybody else!

I will post the name of the first person to give me the answers correctly before next Tuesday. Good luck!

Oh and P.S., if you'd like to receive the crossword puzzle each month, as soon as it's posted, then enter your e-mail address in the box on the Contact page, to subscribe to my free monthly newsletter.

So without further ado, here's this month's puzzle:

Across
1 Kind of clay used as a building material, typically in the form of sun-dried bricks (5)
4 Praise and honor received for an achievement (5)
7 Irritate or annoy (3)
8 Lover of Queen Guinevere (8)
9 Person who leads prayers in a mosque (4)
11 Professional fool at medieval court (6)
13 Book of financial accounts (6)
14 Holiday celebrating the birth of Christ (4)
18 Defensive walls (8)
19 Shout of welcome or farewell (3)
20 Person who tunes pianos (5)
21 Board used to spell out supernatural messages (5)
Down
1 Offer an excuse or defense (5)
2 Industrial city in California (7)
3 Software license agreement (4)
4 More exciting or fashionable (7)
5 Stupid person (4)
6 Large, long-haired breed of dog (6)
10 Creature with torso of man and legs of horse (7)
12 Kettle Drums (7)
13 Comitted to memory (6)
15 Biblical name of Saba (5)
16 Event regarded as a portent of good or evil (4)
17 Capital of Norway (4)