If the forces don't appeal, budget for 250hrs and then a Flight Instructor rating. This will give you the best start in the onshore market (which is where you seem to want to get to).
You would be wasting your money by spending it on an IR at this stage.
If you can't find the funds for 250hrs + FI rating, then think long and hard about committing any funds to a CPL(H) at this stage. They will be wasted.
My best advice? Buy a house. Keep flying occasionally (to have fun(!) and to slowly work your way towards 250hrs). After 5 years, sell the house. If you've been canny (and a bit lucky with the housing market) the equity that you'll earn (£50k-ish) will be enough to fund the rest of your training. Best of all, you won't have to service a loan.
I know that 5 years sounds like an awfully long time but at 24, you'll still be relatively young for this market. If things then work out, you'll be flying an Air Ambulance by the age of 30.
Best of luck with which ever path you choose. Don't worry, it IS achievable.
B73