SeaTruk Thor11  Light weight option with tech tower, Cox outboards - For fishery incursion intercept.
Fast Interceptors 50+ knots for fishery intercept and daiy/night cross chanell surveylance and intercept turnarounds. 
Small Rescue pickup tugs 
Short term patrol boats  drafted 2017
Long-term Coast Guard vessels  x Bae ordered - delivery starts 2018
Fisheries Command vessels  - Rolls Royce made Nowegion design Ram Tug, Low deck with crain and interceptor despatch 
Addition 18.4.17 Announced:
The Maritime Operations Commando Unit is being set up to tackle ISIS jihadis entering the country via boat. It will be comprised of 450 expertly trained troops from the 42 Commando Royal Marines in Plymouth, and liaison officers
from the SAS and the Special Boat Service.
Quite a long [impractical tactical] way from the likely point of [a tactical unlikely attack plan]crossing.. Still pointlessly silly placing response.
details about transport appliances.
The above Comndo unit is a responce fascility for extreme military type insurgent action.
By far the two main service needs in the coming years [Assuming
Britain takes control of its fishing waters & boarders & applies contrtols] are the most rapid & strong response to fishing incursions around Britain & South East & South coast patrol response to small multiple water bound illegal imigration.
For a plan of permanent controls, I would want the following coastal defence capability:
6 x Rolls
Royce UT 515 design [Large Fishery Protection Tug] minumim.
Imigration: [South Coast]
5 x CTruk Thor 19 [Small high speed multi role rescue vessel]
x CTruk Thor 11 [Small High Speed Interceptor Chase Guards] [Outboard Deisels Only] minimum. [Stealth arrest version with night view & external rifle]
Low weight [no armour] with raised Radar bridges.
x Offshore Tug vessels 
Other coast guard duties of counter insurgency & smuggling can be undertaken by any exhisting vesels all to tbe Trakked and under satalite monitoring.
No guarantee regarding British security limits with regard to the channel tunnel.
All of the above are subject to changes without notice.