Sintra

I have not used these guides. However, people in other forums called them out for good service in English:

https://lisbonriders.com
https://www.portugaljourneyswithpeppe.com/

You could also book a guided tour with each individual monument at Sintra.

Happy travels!

THANK YOU ARLENE

I did a small group tour with lisbon riders, but it looks like they also offer private tours.

https://lisbonriders.com/#top