Then you should tell her scorpio that it wont stop at £600 pounds.
Firstly, where are they planning on keeping it? Full livery for a pony can be between £40 to £70 per WEEK. It is less if you DIY but she doesnt sound like she has the time. If the horse is shod, it will need the farrier to visit every six to eight weeks - wince, another £60! even if its not shod it will need its feet checked at least. Then there is vaccinations, wormers (£15 a month if i remember rightly ) Cant remember how much vaccinations cost as i worked in a vets when i was looking into getting a horse so would have got that free. Still coudlnt afford it. What else, insurance and absolute must - my friend has a pony, she gets a discout because she is a vet and it still costs £200 a MONTH I kid you not! Food is actually the cheapest bit. But it will need tack unless he comes with that, often they do - but you are looking anywhere up to £500 for new tack. The list goes on, and on, and on..,,,,,,,,,,,,,,hence i remain horseless.
So, does your friend know ANYTHING about horses, a visit from a vet will cost about £40 before you start, most things wont be covered by insurance as the excess wont cover it etc.
Shetland ponies, whilst lovely are stubborn little feckers and STRONG, My friend has one, he stands about 30" from the ground and pulled me over when i was looking after him and im a big old bird.
So lets think monthly outlay then;
Livery/grazing - £200
Insurance - £150
wormer - £10
Feed - £20
Shoes/feet £30
That is looking at the cheaper options - So, thats what? £410 a month!! She must have money to burn. I know lots of people with horses, they all have good jobs, but will tell you their horses keep them poor.