Replace thermostat in Lec L200G larder fridge

Hi
My larder fridge has heavy icing developing on the middle section of the back panel. After defrosting it it comes back after a few days.

After searching the forums i concluded from other posts that this indicates a thermostat problem.

I am looking into replacing the thermostat. I have changed one before on a hotpoint which was straightforward as it ran completely internally. However having removed the top front panel of the Lec where the thermostat dial is I found the capillary disappears within the insulation of the fridge and is not visible again inside or out. There are no other removable panels inside or out, the fridge appears to have been glued together.

Question 1 is the capillary inside a guide tube and I just pull the old one out and push the new one in by the same amount? (I am loath to pull it out, find no way to refit it and immediately turn my fridge in to scrap)

I am having trouble finding a stat specific to this model and so am considering opting for a generic version suitable for lec larder fridges e.g. Ranco K59.

Question 2 is this suitable?

The markings on the new stat do not correspond to the old stat except the earth. I have 3 terminals (plus earth) of which 2 are connected.

Question 3 Any clues on how to match new to old?

Thanks in advance for any advice you are able to offer

regards

Andrew