TBH it sounds like they do already know what they are talking about as all you've had done is an oil service (minus the microfilter) and the fuel filter..

seem like they've only got to ad the pollen and Microfilter and brake / visual check over to make it into a full inspecion 1 service.. I would just get them to do the extra to make it up to the inspection 1 service and get it all done in one go.

If you take it somewhere else now you'll be asking them to stamp an inspection 1 service when they are only doing half the work as the oil and filter and fuel filter have been done elsewhere.. not sure they will do that for you as if there's a problem with some element of the service where do you take it back to ?

just my 2p..