The money that Cherry comes across is possibly Scottish banknotes (Sterling). Royal Bank of Scotland, Clydesdale Bank and Bank of Scotland all produce their own notes. Widely used all over Scotland and some parts of the rest of the UK. The denominations are unusually large.
When Cherry and she looks in Liam O'Neill's cut for a lighter she finds an envelope full of money, but the money is neither Sterling (GBP) nor Euro (EUR). Technically it should be GBP as Belfast is in the UK. In addition, no-one would have so many £100 notes as they are not common currency anywhere in the UK. Even £50 notes aren't particularly widespread. The common denominations are £5, £10 and £20.
When Jimmy O is in the car in Belfast the registration plate is completely incorrect in layout. The only correct thing is the number of characters and the colour of the plate on the Mercedes. It reads 8WZ 9H51 when in fact all Northern Irish plates read ABC 1234 (3 letters then 4 numbers). If it has a UK mainland plate (which is possible in NI) it can only read A123 BCD (where A is the age identifier character) or AB01 CDE (where 01 is the age identifier).
When Jimmy O is waiting in the kitchen in Belfast, Cameron's cousin calls him "the all seeing, all knowing wizard of East Belfast". With a little bit of basic research they would've realised that East Belfast is predominantly Loyalist area. The main Nationalist/Republican (ie. the IRA) area is West Belfast.