A sample of uk numbers (not a conclusive list but it might help)
023,027 & 028 are local calls for London.
If the client only wants to allow local calls make sure you barr 02476 which is the code for Coventry and is about 100 miles north of London.
999 & 112 are for the emergency services.
09 numbers are premium rate
118 xxx are for directory enquiry services (rates differ from company to company but can be expensive, so I would ask the customer which one he wants to use, If any at all).
0800 & 0500,0300 are freephone (toll free)
0845,0340,0345 are local rate numbers (charges depend on service provider)
0871,0870 not premium rate but can cost a little more than a normal call. e.g travel shops & helplines
ARS DIGIT ANALYSIS REPORT
Location: all
Dialed Total Route Call Node
String Min Max Pattern Type Number
001 9 16 p1 pubu
002 9 16 p1 pubu
003 9 16 p1 pubu
004 9 16 p1 pubu
005 9 16 p1 pubu
006 9 16 p1 pubu
007 9 16 p1 pubu
008 9 16 p1 pubu
009 9 16 p1 pubu
01 9 11 p2 pubu
02 9 11 p2 pubu
03 9 11 p2 pubu
04 9 11 p2 pubu
05 9 11 p2 pubu
0500 9 11 p4 pubu
06 9 11 p2 pubu
07 9 11 p2 pubu
08 9 11 p2 pubu
0800 9 11 p4 pubu
0845 8 11 1 pubu
09 9 11 p2 pubu
1 3 3 p3 pubu
100 3 3 p5 pubu
112 3 3 p6 pubu
04 9 11 p2 pubu
05 9 11 p2 pubu
0500 9 11 p4 pubu
06 9 11 p2 pubu
07 9 11 p2 pubu
08 9 11 p2 pubu
0800 9 11 p4 pubu
0845 8 11 1 pubu
09 9 11 p2 pubu
1 3 3 p3 pubu
100 3 3 p5 pubu
112 3 3 p6 pubu
44 11 12 p7 pubu
5 6 7 p3 pubu
6 6 7 p3 pubu
7 6 7 p3 pubu
8 6 7 p3 pubu
9 3 3 p6 pubu
Hope this helps
D