Also it is not clear from where sage is picking the currency from, when I enter the transactions through inter account transfer window there is no option to select currency so not sure from where it is picking different currencies in a single account. The same transaction is visible with correct amount and currency in sage interface, see snip below

but in the report it shows different currency and amounts 

SYSCurrencies.SYSCurrencyISOCodeID is a link the the (yes!) SYSCurrencyISOCodes table, which has the ISO code for the currency.  48 is usually EUR and 49 GBP but you can't rely on that.

 The Cash Book Inter Account Transfer uses the currencies of the 2 banks you have selected - what do you mean by "different currencies in a single account"?  

Appreciate your response. Yes I am using the inter account transfer so there are two different accounts with respective currencies. 
However it is displaying two currencies in a single account (Euro account side).

The two screenshots pasted in first comment are of same account and txns (EUR bank account) from two sources - UI and the report, however transaction with reference "2312GBP00078" shows £ in currency column but it is a EURO 13000 transaction as per the UI screenshot above. Ideally I would expect the transaction to be displayed as it is visible for the other similar transaction (reference - correction)

To summarize I am trying to understand why it is displaying £ symbol in a euro account and returning £ amounts in the report. (It is correctly displayed in the UI)