Not a clever question. You should tell the TRUTH, and give your legitimate explanation , if you have one. If you don't, the truth will soon come out when checks are made on you, and then there will be NO family permit, as it will certainly appear that your marriage is one of convenience, merely to try to get into the UK. That is sufficient to block your entry, or if you are already in the UK, to deport you.
Apart from that, you have not explained how your girlfriend/wife has managed to be in the UK for 5 years,and at the same time be in Austria. For you to join her in the UK, she would have to show that she can house you and support you, without you becoming a burden on the state. There is no particular sum for that at present, but a senior concerned minister recently stated this should be a minimum of £20,000 a year to support spouse/partner, and more for additional family members.
As to your other question, which seems to be about whether EU countries exchange information on immigration matters, the answer is OF COURSE THEY DO! Especially regarding who has been deported, and why?
Additionally, are you aware that the UK recently imposed more visa restrictions on applications from Nigerians? That is due to the high level of bogus applications, so it is particularly important that you keep any dealings with our Embassies, or the UK Border Agency, simple and honest at all times.
Good luck with your application.