As requested by you, here is a list of places that are Dog friendly, I will link all of them to a review where you can get more details.
There are lots of Dog friendly places however I like to only include places that I have been myself.
Lots of the places listed below have a no access rule for Dogs in the play areas, I would not advise leaving your Dog where you can’t see them but with two people they’re doable or in most cases my partner and I take it in turn to play with the girls and mind our Dog. Always follow local rules. Dogs need to be on the lead on public footpaths.
Some reviews are from my old website so the images aren't as high quality as they were copied over. In time I will update all images. If you want even more ideas, check out my Instagram.
Stanton Low Country Park – Dogs to be kept off the equipment.
Rushmere Country Park – Dogs not permitted inside the play areas.
Wendover Woods – Dogs welcome.
Emberton Country Park – Dogs not permitted inside the play areas.
Newport Pagnell’s River ‘Beach’ – Lots of dogs enjoy this water and large green fields.
Wicksteed Park – Dogs are allowed in the park, however they must be kept on leads at all times and are not allowed in the free children’s playground.
Stanwick Lakes – Dogs are welcome but not inside the visitor centre or adventure play park.
Parsons Close – Dogs not permitted in the play areas and splash park.
Hunsbury Hill Country Park – Dogs to be kept off the equipment.
Lavendon Park – Dogs aren’t allowed in the enclosed section. There’s a dog agility section.
Howe Park Woods – Dogs to be kept on a lead during certain seasons which are clearly signposted.
Irchester Country Park – Dogs not permitted inside the play areas.
Cotswold Wildlife Park – Dogs may be brought into the Park provided that they are kept on a lead. Dogs may not be taken indoors or into the Bat House, Reptile House, Children’s Farmyard and any areas with free roaming animals.
Wimpole Estate – Dogs are allowed in the parkland, wider estate, Stable Block yard and on the terrace outside the Old Rectory Restaurant. Dogs are not permitted in the Hall, Gardens, Home Farm or Restaurant.
Castle Ashby – Dogs are permitted into the gardens providing that they are walked on a lead in all areas of the formal gardens. They may run free in the Arboretum.
Bow Brickhill Wood swing - Dogs allowed on leads due to being a public footpath. Most dogs won't be on the lead once in the woods from my experience of going.
Stony Stratford Nature Reserve - Sometimes there are Cows so keep dogs on the lead.
Little Linford Secret Wood - Keep dogs on the lead on public footpath routes and in on wildlife routes.
Millfield Play area and walk - Dogs not allowed in play area but easy to keep dogs safe while kids playing.
Barton Springs - Dogs on lead on public footpaths.
Great Linford Manor - Nice family walk.
Loughton Lodge Lake - Lake with play equipment dotted around. Suitable for dogs on the lead.
Tear Drop Lake - Nice walk.
Ousebank Gardens - Nice walk, green space through the back of the churchyard. River.
MK concrete cows and tunnel walk - Lots of green space and streams if you walk into Bancroft.
Stonepit field - Field with two ponds, popular dog walking spot.
Floodplain Nature Reserve - Dogs to be on the lead in the nature reserve. Off lead in the surrounds and there's a river.
Woburn Deer Park - Dogs on lead. Known tick area.
Tongwell Lake - A small lake walk.
Willen Lake - Willen lake has changed a lot since this blog with new and different park equipment. I rarely visit as its always so busy.
Olney Park and River - River and field walk.
Stowe National Trust - Luscious walks.