Couple of simple things you could try that wouldn't cost the earth, especially if you can do them yourself!
If it's cutting out, oil light flashing then not restarting it's highly likely to be you Crank position sensor, fits just behind oil filter, one bolt. Costs £50 from GSF and solved most peoples cutting out of the type you describe. The other in to change the ECU relay 30, £12 from VW pull out old one and then plug in new!