Only hassle with an auto and a 16 year old* is that if an auto isn’t worn and left to wind down in a drawer, setting the time and date can be a faff and can damage the movement due to needing to set the correct ‘midnight’ for when the date changes.
Only mentioned as I wear a Seiko 5 and know they can be damaged from the above.
*we don’t have children so don’t know how careful/competent a 16 year old can be. Apologies if I underestimated.
Otherwise Seiko is a good shout – I remember my dad giving me a used one of his when I was young and it having enough kudos. £100 would buy a limited choice 5 from Creation as mentioned above, or double the budget and have more choice buying from the UK. Seiko have expanded their range to include collaborations / street style / murdered out (black colored for older generations) to appeal to a younger demographic. It doesn’t have to be a boring ‘all silver coloured’ old mans watch.