Shareholder perks (benefits) - best value brokers?

Plenty of shareholder benefits out there, but frequently not available when the shares are held in a nominee account, as they usually are.

From MSE:

Shareholder perks

While investments should be chosen for their potential to hopefully make you some money, shareholder perks can be a welcome bonus. These are no longer automatically given as they were when people held paper certificates, but some platforms still pass them on through the accounts.

For example, a simple search will show that if you buy Marks & Spencer shares through a platform such as Hargreaves Lansdown, you'll be sent vouchers offering discounts across the Marks & Spencer product ranges. In order to get these you'd need to get in contact with the broker – the same applies if you want to attend shareholder meetings.

Any suggestions as to the ideal broker combination - low costs and prepared (like Hargreaves Lansdown) to allow individual shareholders to access the various perks, vouchers, freebies etc?