I am in exactly the same position as PompeyPaul and I had prepared a form SRG1119E which I have downloaded from the CAA website, so when I saw the reference to form SRG1157 I was a little confused.
1119E appears to deal only with revalidation by experience whereas 1157 deals with revaidation by experience, issue of a rating following a skill test and revalidation following a proficiency check. Both forms are labelled as current on the website
So I have just spoken with the CAA licencing department who stated that 'they usually deal with the 1119E' when the revalidation is by experience. This form is also a lot simpler because it only deals with one scenario.
Personally, I will present the 1119E to the examiner but have a spare 1157 in my bag in case that is the one he normally uses and knows is OK.
Also, don't forget that 12 take offs and landings are required within the 12 months, as well as the hours and 1 hour with and instructor (sorry if you know that and just didn't put in in your post).
I noted that a pre-recorded message at the start of the phone call told me that 'verbal abuse to a member of CAA staff would not be tolerated', and I wonder why they feel that is necessary? I was feeling quite relaxed until I heard it, but when thought I must be being primed for a frustrating experience I got quite angry and had to kick the cat, (only joking!)