en-GB parses some long dates incorrectly

```
What steps will reproduce the problem?
1. use date-en-GB.js
2. var bad = Date.parse('03 Aug 2009');

What is the expected output?
> Mon Aug 03 2009
What do you see instead?
> Sat Aug 01 2009

What version of the product are you using? On what operating system?
Version: 1.0 Alpha-1 on firefox

Please provide any additional information below.

All formats in dd MMM yyyy format work okay e.g. '03 Jan 2009', '03 January
2009'..

The only ones that don't are dd Apr yyyy, dd April yyyy, dd Aug yyyy. dd
August yyyy e.g.
Date.parse('03 Apr 2009') -> 01 Apr 2009

I wonder if it's related to the letter A at the start of the month name? It
seems that when the month name starts with an 'A' the day part of the date
is ignored.

```

Original issue reported on code.google.com by `paulieph...@gmail.com` on 5 Aug 2009 at 1:24