Here’s what Wikipedia says about the production period for the 10th series:
The read-through for the first production block of the tenth series took place on 14 June 2016. Filming began on 20 June 2016. The second episode was filmed in Valencia, Spain. Shooting for the first block concluded on 28 July 2016. The read-through for the second block took place on 18 July 2016, and filming began on 1 August 2016, beginning with the third episode. Production on the 2016 Christmas special began on 5 September 2016 and wrapped on 30 September 2016. The read-through for “Oxygen” took place on 12 October 2016. Shooting on the fourth block began on 17 October and ended on 18 November 2016. Filming for the fifth block began on 23 November 2016, paused in December for a break over the holidays, and resumed on 3 January 2017 and concluding on 17 January 2017. The sixth block began filming concurrently on 16 January 2017, before concluding on 22 February 2017. On 6 March 2017 the BBC stated that the work on the final two episodes of the series had begun, with Rachel Talalay returning to direct her third consecutive series finale. Filming for the series was concluded on 7 April 2017. Production for the 2017 Christmas special started on 12 June 2017, and concluded on 10 July 2017.