The Ark Royal series starts with the familiar trope where Earth's colonies have been attacked by aliens which outclass Earth's starships except for one British ship, the Ark Royal. There is a twist in that Ark Royal is not state-of-the-art but rather an old carrier that is only kept in orbit for political reasons.
The series mostly takes place in space but any Earth based scenes take place in England which makes a nice change from the USA. Any politics also have a very British slant with a nod to the aristocratic old boy network and the Royal Family.
David Weber is the gold standard for military sci-fi (your opinion may differ) and while Christopher Nuttall isn't upto Weber's standards he still writes a good story. The setting is not inspired in terms of technology, there is some evolution in technology and tactics but not a great deal and combat scenes are competently written.
Where the author shines is writing very human characters and the effect the war has on them. As an example the captain of Ark Royal is a drunkard and battles the urge to drink throughout. The author has also created an interesting alien race although you don't find out much about them until the third book.
My main critcism of the series is the pacing of the third book The first two books are fast paced then you start the third book and it feels like you're moving at Six Million Dollar Man slow motion speed. However the pace does pickup again about a third through the book.
Be warned there are some graphic sex scenes but they're not incredibly long not more than a page at most. If that doesn't bother you and you're looking for decent military sci-fi with better characterisation than most then Ark Royal is worth a try.