Renewal invoices arrive from letting agents every year, framed as administration for processing an extension. Tenants tend to pay them quietly, because the alternative feels like picking a fight with the party that controls the contract — which is precisely why the ground rules here are worth having straight.
Generally not, and it's the same principle as the double-fee ban on new lettings. Processing a renewal is routine landlord-side admin — part of ordinary property management, not a distinct service performed for your benefit — so charging the tenant for it runs into the same "unreasonable advantage" rule that's struck down administratiekosten and courtage fees in other contexts. If an agent invoices you for "verlenging" or renewal processing, it's worth pushing back rather than quietly paying: ask what specific service the fee covers, and if the answer amounts to "updating the paperwork," you're on solid ground refusing it or reclaiming it afterward.