I use myhermes most of the time . They will collect or you can drop it off a one of their 'parcelshops' for about £4 .
Think it's insured up to £50 for that and you can track it too.
There is a link on the site to where your nearest 'parcelshop' is , but it's usually some newsagent within a mile or so of your postcode.
https://www.myhermes.co.uk/Some people don't like to use couriers , but I've never had a problem with myhermes yet .
The Post Office will charge you around twice that if you'd prefer to use them .