Its either, will run on semi or fully synthetic. Fully synthetic is better suited to the engine though. You don't have to use 5-40w either, it can be 0-40w or 10-40w too.
Choice is yours
You'll also find a lot of people are brand snobs with oil, personally any good brand of oil will be suitable (it's not a Ferrari engine despite what people think) so Castrol/Fuchs/Silkolene/Duckhams/Elf or any other good brand will be fine.
Also a point to mention if you don't fancy getting you hands dirty, National tyres do a good deal on oil and filter changes. Will drain, change filter and give you 5L of synthetic for £30, which you'd be struggling to buy the oil for...
http://www.national.co.uk/images/promo/winter_oil_filter.gif
The Visco 7000 stuff is manufacturer by BP:
Benefits to the consumer
The BP Visco brand encompasses a whole range of differently graded oils for different consumer needs. BP Visco 7000, the top-tier, fully synthetic engine oil for passenger vehicles gives the end-user the following benefits:
Ultimate engine protection even at extremely high temperatures
Maximum engine performance
Extra long drainage intervals
Perfect cold starts even at down to -50_C
Keeps your engine as clean as possible
Arrests engine wear
Ultimately, a consumer using Visco 7000 will find their car is better protected, will perform better and last longer. BP helps them and you protect their investment.
BP Visco 7000 is also an engine oil with definite environmental benefits - without compromising performance: Using BP Visco 7000 results in increased fuel savings of up to 6% against the use of a conventional mineral oil
It ensures:
- Maximum emission reduction
- Minimal oil consumption
- Maximum reduction of waste
Some information from BP.