I see your point maxed-out, and a very good one it is too.
Just done some digging around in the office this evening to see what we come up with and here are some extracts.
Cap804: Page 340
FCL.1030(b)(2) – Type and Class Rating Renewal Arrangements
Where the type rating has expired by more than 3 years, or has been removed from Section XII on page 4 of the licence, the application must be submitted to Licensing & Training Standards for the certificate of revalidation entry by the UK CAA, and a fee will apply. Where the type rating has expired by less than 3 years, and is included in Section XII on page 4 of the pilot’s licence, the examiner may sign the certificate of revalidation included in the licence.
It also refers us to FCL740 which states for MEP renewals the following on page 247:
AMC1 FCL.740(b)(1) Validity and renewal of class and type ratings
RENEWAL OF CLASS AND TYPE RATINGS: REFRESHER TRAINING
(a) Paragraph (b)(1) of FCL.740 determines that if a class or type rating has lapsed, the applicant shall take refresher training at an ATO. The objective of the training is to reach the level of proficiency necessary to safely operate the relevant type or class of aircraft. The amount of refresher training needed should be determined on a case-by-case basis by the ATO, taking into account the following factors:
(1) the experience of the applicant. To determine this, the ATO should evaluate the pilot’s log book, and, if necessary, conduct a test in an FSTD;
(2) the complexity of the aircraft;
(3) the amount of time lapsed since the expiry of the validity period of the rating. The amount of training needed to reach the desired level of proficiency should increase with the time lapsed. In some cases, after evaluating the pilot, and when the time lapsed is very limited (less than 3 months), the ATO may even determine that no further refresher training is necessary. When determining the needs of the pilot, the following items can be taken into consideration:
(i) expiry shorter than 3 months: no supplementary requirements;
(ii) expiry longer than 3 months but shorter than 1 year: a minimum of two training sessions;
(iii) expiry longer than 1 year but shorter than 3 years: a minimum of three training sessions in which the most important malfunctions in the available systems are covered;
(iv) expiry longer than 3 years: the applicant should again undergo the training required for the initial issue of the rating or, in case of helicopter, the training required for the ‘additional type issue’, according to other valid ratings held.
(b) Once the ATO has determined the needs of the applicant, it should develop an individual training programme that should be based on the initial training for the issue of the rating and focus on the aspects where the applicant has shown the greatest needs.
So as you can see from the above, yes additional training may and probably will be required to be done by an ATO, however with the way it is written additional training is suggested and should be determined with experience by the ATO.
Now when you come to do your IR revalidation, 99% of pilots will require some sim time in order to get use to the aircraft again and then go and do their tests. From our pool of instructors the average amount of sessions was two. In the information above nowhere does it state that the refresher training must be done in the aircraft. I suggest that in this case your refresher training can happen during your IR sim practices therefore you can complete the MEIR and MEP skills test in one flight, while also fulfilling training requirements.
I suspect if you speak to your flight school they may tell you the same thing and they are the best people to speak to regarding your situation. Unfortunately we do not deal with MEP or SPIR revalidation ourselves so can not comment with absolute certainty, however with the numerous queries we have sent off to the CAA on previous customers behalf, our translations of CAP804 have been accepted.
I hope this helps!