Are my brakes good enough?

I recently failed a MOT for a binding O/S front brake. I had fitted new hose, cylinders (Twin Leading Shoe), new shoes and adjusters before the MOT. I have done this on every wheel but just this one was binding. I have since adjusted it so it will move the same as the wheel that passed.

I then thought I would test to see if the brake was working correctly and drove out of my barn onto a wet field and stamped on the brakes. The rears locked straight away but the fronts didn't. I jacked the vehicle up and started the vehicle (it has a servo) Jammed my foot on the brake and wedged it with some wood. I then tried to move the wheels by hand. I was able to move them a little using all my strength.

What my question is, is should I be able to do that and it not be able to lock up on wet grass? Or is it a case of new shoes and Land Rover drum brakes??

Many Thanks

Don't think you should be able to move them by hand and they definantly should lock up on grass, wet or not.
Also, front should lock first so that may indicate a problem there.

no, they're ****e if you can rotate the wheel by hand with the pedal pressed down hard, get them fixed

my 109 locks all four wheels up even without a servo, i have to lean on the pedal hard

my 88" also locks all four wheels up but less effort is required due to the servo

edit
you may find you need to bed them in a little and readjust them, i'd probably take the drums back off to inspect the shoes to see how much of them are contacting the drum and possibly reassess the drum condition/shoes, you may also still have air in the front brakes as it "can" for some folks be difficult to bleed it all out of the TLS system

New shoes will take a while to bed in, it's worth driving around with the brake pedal lightly depressed for a bit. Overdoing this may well glaze the shoes but this can be removed with some sandpaper. Locking up on grass is dead easy, the rears might have locked first because of the additional engine braking or the landy's weight distribution. Try it on tarmac.

If you've put TLS on have you got the correct master cylinder and is it plumbed in the right way round if it is a dual circuit one?

Have you put the TLS brakes on the right sides

I have not fitted the TLS setup myself it has been on the vehicle a long time and I know with the previous owner it passed MOT's. The vehicle has a servo so I imagine that this has been updated too.

What confussed me was the fact it only failed for a binding brake and no mention of brakes underperforming, or does this prevent the brakes being tested?

I have since decided to replace all the wheel cylinders and shoes as I think the ones I fitted may have come in a blue box and since fitting them I have been made aware of most people opinions!

A have a local truck mechanic friend having a look at them in the week, just to see what I need to do next.

Thanks for your responses