How much more are you will to pay for detached vs semi

[Adjeoebfwh]

Plan to view a house this weekend. The house is detached. A semi in same cul-de-sac with similar size and floor plan was sold for 700k in 2019. This house is up for 850k. SW London. Both houses seem to be decorated to a high standard, beautifully done.

I have never had experiences with detached house so wonder if the price difference is reasonable? Is there sorta of a rule of thumb thing?

I lived in terraces all my life and then an end terrace. My last neighbours were awful and I vowed to never share walls again. I'm detached and it's blissful. I never hear my neighbours.