Can anyone shed light into the internal workings of the Anti-Creep valve.
I am using a 'broke bleed kit' that pressurises the brake pipes to 10PSI then you go from wheel to wheel to simply bleed the fluid out.
With this kit in place I can bleed the front brakes and opening the input connection to the anti-creep valve fluid comes out.
However I cannot bleed the rear brakes.
It looks like there is a pressure operated non-return valve inside the solenoid.

Since no one has responded, I'll chip out n with the little that I know - my car isn't an automatic. The anti-creep should be open with the ignition switched off. With ignition on, closed throttle and the transmission pump not generating pressure, it should be in operation and hold brake pressure in the lines to the rear brakes. There's a switch between the carbs and the solenoid near the gearbox. I don't know the details, but any one way effect should allow fluid to pass to the brakes. If the device blocks, it should make the rear brakes stay on - when driving the car, it would feel as if the handbrake were applied. Hopefully, someone with BW DG box will add some more and correct anything I have wrong.

Likewise Peter, BW35 box on my car so no creep valve and I know nothing about them.
I know on my Hyundai I have a brake hold and an automatic electric hand brake and it is a pain in the ****. There are days when I can't pull away from start as the hand brake is engaged and it is the forward movement of the car that releases it but it doesn't. Takes two or three drops of the clutch for it to disengage which s not good if you are trying to just edge forward a fraction in a parking space.

I have an anti creep valve on my car, but I have plumbed past it.
To try to help answer, I looked through my shop manual which does not appear to mention the thing (have I read that somewhere before?). It is shown in the wiring diagram posted on the S-type regitser, but that does not make very clear where the parts are On The Car. I then went to the brake section on the S-tyoe register and searched "anti creep valve" I came up with a thread where Glyn posted some pics of a diagram of the system and a "shop manual" style drawing, all with drawing numbers in the lower right. Looking back through my manual though I still dont see it. Maybe those drawings are from a different manual? As I read it though, it seems like the valve should be released when the ignition is off. So maybe if yours is engaged it is simply stuck or is wired backwards? In any case I think that if you unplug it, you should be able to bleed your brakes without issue. Good luck and keep us posted-

The anti creep valve is open when there is no power to it so shouldn't cause any issues unless your are trying to bleed the car with the ignition on.

Both my MK2's have them fitted and the S-Type I used to own had one and no problems bleeding any of them, if you are having problems getting fluid to the rear wheels it might be the flexi hose has started to collapse, I would put the system under pressure and crack the lines on both sides of the flexi hose to see if fluid is getting stuck.

It might also be worth trying a bit more pressure if your bleeder can take it just in case something in the valve does need a bite more force to open, I used to use 20-25PSI in mine (pressure from a tyre!)