Had a full service which included replacing spark plugs.  Is there any visual way of seeing if they have actually been replaced?

No, not really, especially if you've got the 1.0 ecoboost as they're quite deep in a recess.

only take one out and look best way ☺️

I’ve found most places will give you the old plugs and the boxes the new ones came in as a matter of course. Not absolute proof they were changed of course, but it leans that way 😂

If you are going to have to take a plug out to see if it has been changed, you might as well have changed them yourself in the first place.

I did not know how to do this or have any tools so hence paid the garage! 

seeing how much they cost it would not be worth it to them not to change them ☺️

Or charge me but not change them regardless!  Stranger things have happened.

19 minutes ago, Jusitne said:

Or charge me but not change them regardless!  Stranger things have happened.

Think it’s time to swap your mechanic if you don’t trust them! 
 

same thing can happen for a lot of things... air filters etc - easy to check but how many people bother? 

Don’t know a mechanic well enough to trust!  

15 hours ago, Jusitne said:

Don’t know a mechanic well enough to trust!  

there's a few spred out somewhere I think 

22 minutes ago, Jusitne said:

Don’t know a mechanic well enough to trust!  

I used to use one that I thought could be trusted but then the quality of work turned out to be questionable at times. So it’s very difficult to get a mechanic that can be trusted, does a good job and doesn’t charge a fortune for it! 

started to use a Toyota main dealer in my area as that’s the car I had at the time. They proved to be really good, trustworthy and very competitive in terms of prices. Surprising combination for a main dealer

Ford main dealers have proved to be a little bit hit and miss. The one I use I’m generally happy with but others on the forum have had some concerns with theirs. 

I had my Mrs's little SEAT serviced a few week ago. The lad at our local garage was almost apologetic for changing the plugs but said he thought he should as it was 5 years old (even though only very low mileage). No need to check - I could feel a difference just driving home!

Ford garage told me that I probably wouldn’t notice a change which I haven’t, so who knows if they were changed or not  Gotta trust folks i suppose.

A lot of the small turbo engines have long life plugs, usually iridium or platinum, other than checking the gap and condition they rarely actual "need" changing on a modern clean burning petrol.

 

As for the seat (or any vag brand), if it was one of the 1.2 or 1.4 turbo engines there is a good chance of oil contamination/build up which can lead to a misfire that is often mistaken for coil pack Failure, the ceramic can break up when they misfire from carbon build up as well (pre ignition)

 

The ECU cannot tell the difference between a misfire from coil stick or plug, but you can bet 10 to a penny that if one coil stick goes down the rest will not be far behind.

 

They will attempt to "hide" the affected cylinder to keep the engine running at reduced power, which might be why you noticed a difference.

40 minutes ago, prawny1 said:

if it was one of the 1.2 or 1.4 turbo engines 

Lol - it wasn't that big a difference - my Mrs never noticed anything at all - I just have a bit more "mechanical sympathy"! It's a n/a triple btw.