Create a field which has a currency symbol and an amount (with commas)

Hi all, 

I have a very old SharePoint list which I want to update without breaking any of the existing functionality. 

There are 2 existing fields: 

1. A currency field (which is a choice - £/€) 

2. A string of a number up to 10000000 (without commas) 

What I would like to do is concatenate the currency choice and insert commas in to the resulting field. So for example: 

Existing fields : £ and a string of number - e.g. 10000 

What I want : £10,000 in a new field 

There is an underlying workflow so editing the fields will kick it off, which I don't want. I have managed to convert 10000 to 10,000 in a few field (using =VALUE([Request Amount])), but ideally I'd like to add in the currency at the start. 

Is this possible in SharePoint 2013? 

Thanks for you help, apologies I'm a SP newbie.