Update 17 May - spoke to Alley Cafe - they are normally quiet on a Monday evening so were all right with increasing booked seats to 16 (excludes maybes).
Based on the Poll the most popular evening was Monday 20 May.
Have booked 8 seats for 6pm the moment. Alley Cafe closes at 9pm on a Monday.
Alley Cafe are generously offering their food at 1/2 price during National Vegetarian week Monday 20/05/2013 @ 11:00 am – Friday 24/05/2013 @ 9:30 pm.
From their site:
"We are delighted to offer all our customers our full food menu @ 1/2 price from mon – fri during National Vegetarian Week. Eat, enjoy but don’t eat too much or you may pop
[excludes all existing offers, discounts and vouchers]" - checked today while booking seats and was told it covers the printed menu and soup and pate from the written board (which appear in the printed menu) - but not the daily specials.
So if you have not been there this is an ideal time to try it out.