Many thanks for your advice!
I initially planned FL100, but as you said, apparently, London Control likes quite a lot FL090, therefore I might go for that FL instead.
The route you found out, it will probably be the most direct one; unfortunately what Eurocontrol does not seem to know, is that according to AIP AD EGTG section, easterly IFR traffic inbound shall route MALBY - OF. That's why I went for the aformentioned route.
I will take the chance to have a long IFR flight, as I'm sure it's a nice experience on a GA a/c.
I have read your email, many thanks indeed; I found your website really useful, and I loved the video in the homepage...!
Again, many thanks!
amcapt89