I have a forum at http://www.digital-kaos.co.uk. I have a sitemap on google webmasters for this location. I also have a sitemap on google for http://www.digital-kaos.co.uk/forums. Will I benefit from having these two sitemaps? Is the bot going to crawl both sites eventually or will it help them to crawl faster. Thanks.
If you have a large website having different sections within it like blog,forums etc...then it is good practice to use different sitemaps. It helps your website in regular crawling..
Around 1480 pages indexed from your website. And only forum implemented in your site. So it would not be useful to add 2 different sitemap.