A quick google shows the app will cost c£35 million[1], while the overall cost of the Mars Perseverance programme is $2.7 billion[2]. 10 times $2.7 billion is $27 billion so you are out by a large factor.
[1] https://www.digitalhealth.net/2020/09/total-cost-of-nhs-cont... [2] https://www.planetary.org/articles/cost-of-perseverance-in-c...
The budget for the overall NHS Test and Trace system was £37bn last time I checked, and lots of news outlets seem to be trying to conflate that budget with either the cost of the tracing system (which didn't work very well) or the cost of the app. In reality, the vast majority of the spend has been on testing, and some of that budget likely remains unspent.
https://blogs.bmj.com/bmj/2021/03/19/covid-19-test-and-trace...
Why add in 36.9 billion of other costs? (other than to distort it to make it look much more expensive than it is?)