Just a quickie
A May 05 GTI 50K T&D VW services from new...
Do you know what spec oil was used?
Nope - just says OIL or Castrol oil on the service invoices.
Do you recommend engine flush at this age? Hear both sides of the coin all the time. Sludge etc can cause blockages when "dissolved"/shifted by the flush or the flush gets rid of the impurities which can't be a bad thing.
Flushing oil is generally NOT needed. Modern high quality oils have enough detergents and dispersants in them not to cause any sludging issues. However, if some cheap, non-fully synthetic oil has been used in a turbo engine (as the yanks seem to do), then you will get sludging.
So can I use a flushing oil as I don't know that the correct Castrol Powerflow SLX was used? Also the oil after just a thousand miles looks very dirty. Either a proper service has not been done or the engine internals are VERY dirty. I hope a flush would help clean this dirt as much as any sludge.
Still wishing to check the school of thought regarding causing more harm than good with a flush.
Plan on doing oil changes every six months or so spring & autumn. Spring one yo get rid of the moisture etc after cold winter starts and cold running.
Are you only doing short journeys? 
Quite a mixed bag of journeys. Although a lot are short or in traffic. - I am from the old school before the synthetic stuff came on the market. Since then until now I have had company cars, serviced by the company at regular intervals. This is the first car in about 20years that I have rolled my sleeves up and had a go. Quite enjoying the experience too, gets you away from the other half too. 
So 6,000 mile services were the norm on old Fords... seems I am a little out of date, but regular services surely can't harm, just a waste of beer tokens?
Thank you for your help and informed opinion.
I would actually strongly advise against using a flushing oil. In all honesty, flushing oils should only be used in quite specific circumstances. Dark or even black engine oil which has previously been changed on schedule is NOT a requirement for using a flushing oil.
Onto the reasons why new oils go black very quickly (excluding those engines who use the devils fuel - diesel
). LAZY STEALERS - quite simply, incorrect oil change procedures.
Some stealers will use an oil extraction tool, which is basically a vacuum cleaner shoved down the dipstick tube - and these can NEVER extract all the old oil. These oil extraction procedures are categorically NOT permitted by Audi, yet VW seem to tollerate them. Engines have a sump plug for a reason, and any so called 'mechanic' or 'technician', who can't find a 19mm ring spanner to undo the sump plug just doesn't deserve to working on vehicles of any kind. The only acceptable use of oil extraction devices are on marine engines. Period!
Secondly, many stealers fail to actually carry out the correct procedure (even those who do use the sump plug). On ALL engines, the oil filter MUST remain 'removed' during the duration of the drain. Way too often, I see incompetents who first remove the oil filter, and then replace it - BEFORE removing the sump plug. This prevents a total drain of the old oil.
Finally, oil changes really need to be done whilst the oil is hot, ideally at normal operating temperature, and certainly within a max of 30mins since turning off the engine. If not, any 'contaminents' in the oil can fall to the bottom of not only the sump, but also any other point of the engine where oil pools (the cylinder head around the camshaft is a common) - rather than remaining in suspension.
