Galaxy 57 plate 2.0TDCI Turbo Issues

[Ellindor]

My car recently started to make a fairly loud whining down noise when I took my foot off the accelerator. It sounded like the turbo whining down? RAC looked at it and said the hard plastic pipe from the turbo going down under the sump was cracked. Took it off, couldn't find a crack, after re-fitting, the noise stopped for about a week. Started doing it again when I put my foot down hard, but less frequently and quieter.

Ford listened to it and said they THINK its the dump valve sticking and that will be £1300 please! they didn't even open the bonnet.

I don not want to pay thousands on a part that MIGHT be the problem.

Can anyone recommend somewhere to take it to get a definitive diagnostic? Im based in Swindon, Wiltshire.