If you're not so worried about having the 0700 on the front, then Skype has an interesting alternative.
You can have a SkypeIn Number and re-direct your Skype account over SkypeOut to a landline or mobile number.
This has some advantages over 0700. Firstly, your SkypeIn number will be a normal landline number (eg. 089) so friends calling it will be able to include it in their flatrates. Then, if you answer the call using Skype, you don't have any call-forwarding costs. Forwarding costs otherwise depend on your Skype tarif (normal or pro).
Since Skype forward overseas at their normal rates, you can forward eg. to a land line in the UK for the normal price of a Skype call, rather than the "0700 forward to an overseas number" tarif.
SkypeIn is also slightly cheaper than 0700 (5EUR per month or 50EUR per year, plus
MwSt).
The other thing that I like is that you can have SkypeIn numbers in other countries, so while your friends in Germany call you on 089... you can have a UK number (London, Birmingham etc.) ie. 020 ... or even a USA or Australian number. Your friends and relatives there call you at their inland rate, and the forwarding to Germany is effectively free - you only pay for the little bit within Germany to the landline or mobile.
Also, you can forward Skype to three numbers simultaneously, so you can setup your landline and mobile as destinations and don't have to keep logging on to change the desitantion number.