In you case you want to get rid of the static default route and you want to peer with your single ISP, do you need to announce any routes for your side ? I have the below config, is it enough for peering with your ISP ?
ip prefix-list default permit 0.0.0.0/0
Router bgp xx
no auto-summary
no synchroniszation
Neighbor x.x.x.x remote-as ISP (peer to ISP)
Neighbor x.x.x.x password xxxx ( basic authentication)
Neighbour x.x.x.x prefix-list default in ( accept default only)