I've the next rewrite rules:

#remove the www.
RewriteCond %{HTTP_HOST} ^www.website.co.uk$ [NC]
RewriteRule ^(.*)$ http://local.website.co.uk/$1 [R=301,L]

#this removes php extention
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^\.]+)$ $1.php [NC,L] 

# stops you accessing url with.php
RewriteCond %{THE_REQUEST} ^[A-Z]+\ /([^.?\ ]+)\.php
RewriteRule ^([^.]+)\.php(/.+)?$ /$1%{PATH_INFO} [R=301]

I wish to include a guide that removes the trailing slash if a person attempts to access site with one.

eg

website.co.united kingdom/cheese/ should redirect to /cheese

as you can tell I've got a rule that redirects ursl using the .php extention, unsure where to start.

I actually do have directory within the root folder which I don't desire to take away the trailing url, however i can also add a ignore rule for individuals.

Cheers

Result in the change below for your .htaccess file

RewriteEngine on
RewriteBase /

#existing rule
#remove the www.
RewriteCond %{HTTP_HOST} ^www.website.co.uk$ [NC]
RewriteRule ^(.*)$ http://local.website.co.uk/$1 [R=301,L]

#new Rule
#if its not a directory
RewriteCond %{REQUEST_FILENAME} !-d
#and it has a trailing slash then redirect to URL without slash
RewriteRule ^(.+)/$ /$1 [L,R=301]

# rest of your existing rules go here