more cycle trailer funny business.

[Gareth]

That's fab, however, way beyond my technical skills!

No it is not, if you can remove and install a wheel and brake blocks, you can do this.
The only real issue is locking the suspension frame in position with some tubing and nuts and bolts. Although I have not made one of these for 3 years I have helped others on community projects to make 6 of them during the last 6 years. The most notable was a young lady of 18/19 years old who could very easily have "gone the wrong way." Anyway long story short with a little help from me, she ended up making a long tail bike from a 26" wheel Probike BSO and an old BSO rear suspension frame. This bike she used to start a gardening round and event flower arranging business, and 5 years on she has up graded to an electric assist Bakfiets and trailer and seems to be doing very well.

 

[Sara_H]

Well, we found a metal grid thing in the shed that used to be for enclosing the dog into the hatchback and zipped tied it on. It doesn't quite fit but seems secure. Then we bungeed a laundry basket on to hold his sack.
It looks like this:

This may not be the final solution!

 

[classic33]

Bungee cords will be cut by laundry basket, as it moves around.

Use something that can't stretch, causing movement.

 

[Sara_H]

Bungee cords will be cut by laundry basket, as it moves around.

Use something that can't stretch, causing movement.

I was planning to use some ratchet straps, they will probably be better. I was surprised son went for the laundry basket idea. I was on the lookout for a bakers basket or similar.

 

[classic33]

Baker's basket would allow any water to escape though.

Measured what I use, too big for your requirements.

 

[ufkacbln]

A couple of "T Plates" would secure that easily

Use one as a pattern and drill through the basket

Then use a second one to sandwich the basket and a couple of the grid "wires"

Repeat at other end

If you use domed bolts' there will be nothing at the bottom of the basket to catch and tear the papers