[damien_ls]

If your site is using a .uk domain then it should be listed in the localised listings (e.g. Google UK) already and therefore it's unlikely that IP "location" would have any further bearing in that respect.

However, changing to a UK host may provide faster page response times for your UK visitors... but latency to Germany shouldn't be so bad, so the impact of this might not be worth your trouble. Assuming that it would help your site load better, it would provide a better user experience and therefore you can expect to receive more traffic / relevant inbound links.

The additional inbound links almost certainly would help you in terms of SEO.

With regards to uptime, I'm not convinced that this has an impact on SEO from the search engines point of view - if the site is unavailable when they wish to spider they'll be back another time.

However, if your site is down then obviously people won't be able to look at it, and are unlikely to provide links to it etc. and this would negatively affect SEO.