I'd say it's a little on the low side for a graduate salary.
National minimum wage for a full time job is roughly £25k from April 26.
Average wage is around £39k.
BUT a lot depends really. Is it a "training"/"apprentice scheme" job where the employer is paying for your ongoing, maybe professional, training, time off for study leave & exams, or providing in house training?
What's your trajectory for pay rises, promotions, etc?
If your starter salary is £30k, but with training, promotions, etc., you'll be on £40k within a couple of years, £50k-£75k within 5 years, then it all seems good. But if you're still going to be on £30k next year, and maybe only £40k in 5 years, then it's really not good at all.
You also have to look at other "perks" - do you get a better holiday entitlement than the legal minimum? How much employer pension contributions are they making? Do you have enhanced sick pay, maternity pay, etc.?