Had a new vent fitted and new seal fitted
But the vent on the side of a housing boxing is giving off fumes want a charcoal filter to place on the vent it sent on the housing inside so smells don't come through unfilted smells better where can I get them from

You should not have a waste vent installed out of code, and it sounds like you have?
Your writing could be clearer.
Masking smell with charcoal won't save you if you die, so I'm not going to help.

Its registered correctly and the plumber as met requirements it seems swapped the vent for a new one and replaced the seal
But the vent in the bedroom is emitting smell every now and then and advised could get a charcoal vent filter can seem to get from uk plenty places in usa

Buy from the US and buy an inch to metric adapter in the UK.
Try amazon - not all places will ship out of the US.