Hi @Anonymous User
Shouldn't be a problem taking up an entertainment offer on your account, together with your F1 sports pass offer.
Where normally you can have separate offers on each type of pass and can add a new offer within the last 30 days of an existing offer coming to an end (not sure how it works should you be an old NowTV Combo customer though).
With regards to a NowTV entertainment pass you will get access to live TV, catchup and boxsets so Game of Thrones won't be a problem.
Personally i think 3 months entertainment for £18 is not a great deal offer if you ask me, where you will save more money by looking at a NowTV Gift card entertainment voucher for 2 months for £10 which should cover Season 8 of GOT and any other entertainment shows you wish too watch over the 2 month period.
If you are interested you can buy the NowTV Gift card vouchers from places like Argos, Curry's, Major Supermarkets etc.