I've a client who's site I'm currently working on. We made a temporary site with WP to give him a presence whilst we're building the main site but he's contacted me with a bit of an odd request regarding his contact form. In the 3 weeks the temporary site's been online, he's had a fair amount of spam coming through. He wants to stop this on the new site but doesn't want potential customers to be put off by by a captcha which can be difficult to read especially for older people (his words not mine). Is there a suitable halfway house?