given that you're uk.. beyerdynamics cans are a good price. look at the dt770, dt990 and dt880. i know the 770/990 hover around 100-110gbp normally. i would get a decent amplifier for them as well with the remaining money. for the 770 the fiio a3, e12, schiit magni are all good. for the 990 e12, magni, o2, similar are good. for the 880, same as 990.
770-80 version is a bit easier to power so a cheaper amp can be used and is the bassier version 770-250 is a bit more refined but you will want a slightly better amp. the 990-250 and 880-250 also would need a bit more of an amp. you want the pro models as the premium ones are jacked up in price.
770- v-shape sound signature. has lower bass extension, closed
880- more neutral and slight v-shape. less extension into treble (less harsh) and less extension into bass (less bassy), open
990- v-shape sound signature. fairly bright and good bass for open cans.
good soundstage on any, but open cans are of course much much better for that
see chart
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how to read? 0 line is horizontal in middle. frequency range is low tones left and high tones right. the higher the peaks vertically the more the headphone puts out those tones. the lower and the least it puts them out. for example if it peaks on bass, drops in mids and peaks on treble you have a v-shaped headphone. this will appear to sound bassy but with good detail in treble but with recessed mids. completely flat (which is not possible) would be neutral so anything mostly flat will sound balanced across the board and neutral between bass-mids-treble