I saw my first Shrill Carder today in a nice area near the Port Talbot docks next to the river Avon. Thanks go to Elen Richards who discovered this population last year. I only saw one bee today which was a male but the species is so named after the workers that can be heard to give a "shrill buzz" when flying between flowers whilst foraging.
Shrill Carder Bumblebee (Bombus sylvarum)
Following the comment below I realise that I've made a very basic mistake with the identity of this bee. As mentioned in the comments the bee is B. pascuorum.