This code will pull out the header information from the first 1000 lines of all the fastq's in the folder where it is executed. Then it takes the most commonly found index and outputs a summary for each fastq.

Check_Fastqs.py

#!/usr/bin/python
import re
from itertools import groupby as g
import subprocess
import sys
from collections import OrderedDict

def most_common(L):
  return max(g(sorted(L)), key=lambda(x, v):(len(list(v)),-L.index(x)))[0]

# Set this variable to ensure no quality score lines get examined.
fq_at_start = "HWI"

r = subprocess.check_output("""
for r in `ls *fastq.gz`; 
do
echo "$r" 
gunzip -cq $r | head -n 1000 | grep '^@%s' - | grep -v '^@@' |  egrep '(:.+){4}' -
echo "|" 
done;
""" % fq_at_start, shell=True)


f = open("fastq_summary.txt", "w")
 

orig_line =  OrderedDict([("file", ""),
			("instrument", ""),
			("flowcell_id", ""),
			("flowcell_lane", ""),
			("x_coord", ""),
			("y_coord", ""),
			("index", ""),
			("pair", ""),
			("run_id", ""),
			("filtered",""),
			("control_bits","")])
l_keys = orig_line.keys()

f.write('\t'.join(l_keys) + "\n")
 
for fq_group in [filter(len,x.split('\n')) for x in r.split("|")][:-1]:
	index_set = []
	for heading in fq_group[1:]:
		l = re.split(r'(\:|#| )',heading)
		line = orig_line
		line["file"] = fq_group[0]
                if l[0].startswith("@SRR"):
                    line["run_id"] = l[0]
                    line["instrument"] = l[2]
                    line["flowcell_lane"] = l[4]
                    index_set.append("")
		elif len(l) == 11:
			line["instrument"] = l[0]
			line["flowcell_lane"] = l[2]
			line["flowcell_tile"] = l[4]
			line["x_coord"] = l[6]
			line["y_coord"] = l[8]
			try:
				line["pair"] = l[10].split("/")[1]
				index_set.append(l[10].split("/")[0])
			except:
				break
		elif len(l) == 21:
			line["instrument"] = l[0]
			line["run_id"] = l[2]
			line["flowcell_id"] = l[4]
			line["flowcell_lane"] = l[6]
			line["flowcell_tile"] = l[8]
			line["x_coord"] = l[10]
			line["y_coord"] = l[12]
			line["pair"] = l[14]
			line["filtered"] = l[16]
			line["control_bits"] = l[16]
			line["index"] = l[20]
			index_set.append(l[20])
		else:
			print "error", l
	line["index"] = most_common(index_set)
	f.write('\t'.join([line[x] for x in l_keys]+ ["\n"]))

Updated to work with two variants of fastq lines.