Swapping Links

Always happy to do a link swap for our clients to enhance their local standing and SEO, and actually recommend them to swap links with similar businesses in their local area. But sometimes their link swap requests or suggestions are not in their interest, meaning the website wanting the link will gain more than the other website owner (my client). If this is the case I will tell them that their link to the other website is worth  more (in terms of SEO ‘power’) than your link back and would advise against such a  link. If you own a website you will probably get lots of link requests on a weekly basis so its worth looking at the SEO usefulness of links that are offered to you.
Recently we had such a request from a Brentwood Website, to give some flesh to my argument here are my reasons given, after the company had already put a link to my client on their website in anticipation of the reciprocal link back to them.
My Clients link on their website is on one page of 20 links pages on their site and its not an optimised link (no anchor text and no description of your services), additionally the links page my client was placed on is not linked from the front page and their site is not as highly ranked (Google Toolbar pagerank) as my clients. My clients links page also has its own Google pagerank making it much more valuable than theirs.
In SEO terms I considered the link proposed from my clients site to give them is worth 8 out of 10 (relative scoring) but their one is worth 1 out of 10. Swapping links is a recognised SEO strategy but this swap is not fair for my client’s website, meaning it will leak some of its valuable ‘Google Power’ (SEO).