May I ask op, are you seeing the consultant only because of your pgp? Because (unless you have some serious medical condition) in some cases (such as bmi over 35, or if you're a bit older than 35 or whatever) you don't have to be under consultant led care, it's your choice and you can argue it and ask to be put back under midwife led care. It's not as if the consultant can do anything about the pgp anyway other than maybe get you a support band. Obviously if you do have a medical condition then that's different!
I say this because if you're under consultant led care it will pretty much ensure a medicalised birth in a hospital bed. That's not to say it will be awful or anything like that, but from experience if they consider you high risk they tend to rule out the birth pool and birth centre.
They did this with me purely because I'm overweight (I don't have any health conditions) which is why I hired the independent midwife to support me in a home water birth, because I knew they'd never let me have one at hospital. And it was another perfectly normal pregnancy/baby/birth, no issues. But according to them it would all go horribly wrong, despite no evidence to the contrary, all scans and tests saying everything was perfect. 
Consultants are very keen on everything being very controlled, because they think everyone is out to sue them hence the constant monitoring, which is only possible if you're lying down still throughout, which is bad for any pregnant woman, pgp or not, because the weight of the baby is pressing on a major vein, limiting blood flow for mother and baby. And as I said earlier, you're not benefiting from gravity, effectively you're pushing the baby uphill (and the pelvic outlet is reduced by up to 2cm because your bottom is on the bed)
So you can see that despite all evidence about keeping upright being best for women, water being great for pgp etc, in most hospitals currently they still don't bother because it's easier for them to confine you to a bed where they can see what's going on (because their ease and comfort is the priority here of course!) 
If you do want a water birth I'd recommend doing what I did and speaking to the supervisor of midwives, telling them how you feel, and asking what they recommend for women with severe pgp who want to avoid lying on the bed in stirrups. The bed should not be the only option. And if it is, ask about birthing centres, or home birth. They can't make you do anything, it's up to you. Once you start saying "I'll just have to have a homebirth then" it's surprising how quickly they start saying "Er, well, ok we'll let you labour at the birth centre/pool!" 