The bank should require the Hard Morytania Diary completion, and the altar should require the Elite diary to be completed.
On top of this, I would make it so the altar strictly requires you to be on a slayer task as well.
Why? Vyres being extremely AFK (as opposed to e.g. pickpocketing vyres which is absolutely not AFK) causes BF price to be... obnoxiously cheap for how good of an item it is.
Why Hard/Elite tiers? The Hard tier of the diary is pretty easy, I mean if you've done SotF you should easily be able to do this tier. The bank still requires you to bring your vyre noble outfit + requires you to use your own supplies (namely prayer and combat potions).
The Elite tier of the diary is also pretty easy (especially for mains) - the only hard requirements are 85 (80) slayer (which is easy on mains) and 96 (91) fishing, which is very quick to get (even faster on mains; 2.5 tick barb fishing), but requiring the elite tier + being on a slayer task is fair enough for essentially infinite free prayer restoration - i.e. giving vyres that "afk" status it's known for.
Edit - Also, to append to this, for those saying that fishing is "ungodly slow" or whatever bullshit, 70 -> 91 fishing is under 40 hours. Sure, you might not want to tick manip or w/e, but at the end of the day you choose to do afk methods because you want to afk, and you accept that you'll get worse xp as a result.



