oh - so its simply what some places call administering the DNS or changing the Nameserver records?
For eg I purchase my domain name from company 'x' - but in their control panel I point the name server records to my webhosts, who are the ones that deal with my mail.
I know that your ISP gave you some free webspace but irrc there wasnt any control for proper administration with the domain name.. so now may be the time to start looking at some separate hosting which will allow you proper control of your webspace and also email.
Whilst it may not be the cheapest package.. the £17 per annum package from
Vidahost does seem pretty good value for UK hosting and includes a lot of stuff not normally found from the likes of 123.reg such as CPanel (which gives you a lot of control how your domain is administered) .
Up to 5 subdomains.. 5 SQL databases and allows php.. so you can even run forums - unlike say with 123.reg.. which makes it IMHO an overall very good deal.