Grado. Grado. Grado. 
SR80s are GREAT open headphones for £100 - if you want to you can spend £4000 on Grados (which is an established US family business). If you insist on using headphones for mixing, open headphones are the only way to go for eq’ing, mixing and stereo field appraisal and also critical listening.
They can be useful in the early stage of mastering. For final mastering there is no replacement for quality near-field monitors. (And golden ears )
Recording vocals or acoustic instruments (tracking) requires the performer to wear “closed” headphones if re-recording the cue/backing track - via headphone “bleed” - is to be avoided.
I hope this helps 