in general terms you cut the backthorn down to encourage a mix of habitats then stack it up in habitat piles for invertebrates to live in while the piles slowly rot down - if butterfly eggs were present they would be very small and it is very unlikely that you wouldhave squashed them all.
regarding the part time welfare assistant have you actually got the position or do you still have to be interviewd etc - Also I dont want to rain on your parade but you do realise that a welfare assistant spends most of there time cleaning out cages and moping up pee dont you
also i would really suggest thast you try to keep things in proportion - whether you get the job or not its a job , not the end of the world , some people have real problems and face much more adversity every day of their lives than not being able to get a bus to burford