longlegbog

[Best]

I fitted a new high toilet pan to replace an old low level pan for a neighbour.
From memory it was about 18 or 19" high & therefore with a seat it might be near your required height of 525mm. It was really nice & solid pan for just over £100 & made in UK. 30 stone is a bit heavy for any china!
I will get back to you when I get the details.

 

[Best]

Take a look at Lantac L/L DOC -M.
I got only the pan for a low level toilet & I see it is 480mm high. With a substantial toilet seat it will be close to your required height. Not sure if it will be good for 30 stone person tbh. Would be in your budget.

Also I came across this toilet - Doc M Standard Left Or Right Hand Hand Packs | Doc M WC Rooms | Doc M | Bluebook | IdealSpec

 

[REDSAW]

think the easy/price way is build a plinth. bolt to floor and refix pan. that keeps it fitted as standard!.
suitable, idk?

or just tell her to get someone who specialises in this sort of problem.

geez, give me a boiler to service instead lol.