Engine oil grade

Just wondering what engine oil grade people are using in 1.8 dx engines,just noticed it says 20/50 in manual but 10/40 is very common in shops these days,does this make much difference?

Oil has changed since the Haynes was printed, most people use 10w40 semi synthetic.

Stuff I've been using for about 10 years no problem.

Use discount code to get it cheaper.
http://www.eurocarparts.com/ecp/p/car-parts/engine-parts/engine-parts1/engine-oils/?521776011&1&cc5_245

Or here, again use discount code.
http://www.carparts4less.co.uk/cp4l/p/accessories-engine-oil/engine-oils/engine-oil/10w40-engine-oil/?521776011&0&cc5_245

Stuff VW would stick in.
AVS Car Parts

Make sure you use a genuine VW or Mann oil filter, VW filter can be bought from AVS (link above) Mann filters from Euro or car parts 4 less.
New sump plug washer is also needed, 45p for a new one.
http://www.carparts4less.co.uk/cp4l/c/Volkswagen_Golf+Cabriolet_1.8_1988/p/car-parts/engine-parts1/engine-parts/sump-pans-and-sump-plug/?333771291&1&47c8751ced189bff5450784e05f1acd1b6276fd2&000567

Yeah 10w40 semi is what I use. 

Thanks guys!