Which UK counties have coastline?

coastline.R

library(sf)
library(rmapshaper)

# Grab shapefiles, here from http://www.diva-gis.org/gdata
shps2 <- read_sf("GBR_adm/GBR_adm2.shp")
shps2s <- rmapshaper::ms_simplify(shps2)
outline <- st_union(shps2s)
outline_flat <- st_transform(outline, crs = 27700)
counties <- st_transform(shps2s, crs = 27700)
outline_5km_in <- st_buffer(outline_flat, dist = -5000) # 5km inland
donut <- st_difference(outline_flat, outline_5km_in)
vv <- st_overlaps(counties, donut, sparse = FALSE)
shps2$NAME_2[which(vv)]

# [1] "Brighton and Hove"        "Bristol"                  "Cheshire"                
# [4] "Cornwall"                 "Cumbria"                  "Devon"                   
# [7] "Dorset"                   "Durham"                   "East Riding of Yorkshire"
# [10] "East Sussex"              "Essex"                    "Gloucestershire"         
# [13] "Halton"                   "Hampshire"                "Hartlepool"              
# [16] "Isle of Wight"            "Kent"                     "Kingston upon Hull"      
# [19] "Lancashire"               "Lincolnshire"             "Medway"                  
# [22] "Merseyside"               "Norfolk"                  "North East Lincolnshire" 
# [25] "North Lincolnshire"       "North Somerset"           "North Yorkshire"         
# [28] "Northumberland"           "Plymouth"                 "Poole"                   
# [31] "Redcar and Cleveland"     "Somerset"                 "South Gloucestershire"   
# [34] "Southampton"              "Stockton-on-Tees"         "Suffolk"                 
# [37] "Thurrock"                 "Torbay"                   "Tyne and Wear"           
# [40] "West Sussex"              "Ards"                     "Armagh"                  
# [43] "Ballymena"                "Belfast"                  "Carrickfergus"           
# [46] "Castlereagh"              "Coleraine"                "Derry"                   
# [49] "Down"                     "Dungannon"                "Fermanagh"               
# [52] "Larne"                    "Limavady"                 "Moyle"                   
# [55] "Newry and Mourne"         "Newtownabbey"             "North Down"              
# [58] "Omagh"                    "Strabane"                 "Aberdeenshire"           
# [61] "Aberdeen"                 "Angus"                    "Argyll and Bute"         
# [64] "Clackmannanshire"         "Dumfries and Galloway"    "Dundee"                  
# [67] "East Lothian"             "Edinburgh"                "Eilean Siar"             
# [70] "Falkirk"                  "Fife"                     "Highland"                
# [73] "Inverclyde"               "Midlothian"               "Moray"                   
# [76] "North Ayshire"            "Orkney Islands"           "Perthshire and Kinross"  
# [79] "Renfrewshire"             "Scottish Borders"         "Shetland Islands"        
# [82] "South Ayrshire"           "Stirling"                 "West Dunbartonshire"     
# [85] "West Lothian"             "Anglesey"                 "Bridgend"                
# [88] "Caerphilly"               "Cardiff"                  "Carmarthenshire"         
# [91] "Ceredigion"               "Conwy"                    "Denbighshire"            
# [94] "Flintshire"               "Gwynedd"                  "Monmouthshire"           
# [97] "Neath Port Talbot"        "Newport"                  "Pembrokeshire"           
# [100] "Powys"                    "Swansea"                  "Vale of Glamorgan"