The heart of this issue, ie how the OJT is dealt with by these places, is the definition of an "Approved" course, the fact that the requirement for work experience following an approved course is 2 years instead of 5, and the reasons for that difference.
An Approved Basic course has 3 essential ingredients. The Module exams, the Practical Training and the On-the-Job Training (OJT). The whole course, including the OJT, must be provided by a Part 147 Approved Maintenance Training Orgnaisation. However, the OJT must be carried out in a Part 145-approved Maintenance & Repair Organisation (MRO). Therefore a Part 147 MTO should have a contract with such an MRO as a necessary condition of its Part 147 Approval. Clearly in the UK some do not, and EASA should take an interest in why not.
The OJT must be supervised and directed by the Part 147-approved MTO, and the contract with the Part 145 MRO must facilitate that. A typical charge by a Part 145 MRO for facilitating OJT, which takes place within its own Part 145 procedures and Quality Management, would be £500 - £1,000 per day for a group of up to 6 students, plus an amount per student. There is a lot of additional administration involved.
When a student is sold a "Fully-Approved Basic Training Course" that must include the OJT, by definition, so that no students should be told to go and arrange their own OJT.
If it does not, it ceases to be a Fully-Approved course, and this is where the work experience issue comes in. The alternative route to a licence is to pass the Module exams in any way you can, normally with a mixture of home study, short intensive courses for some Modules, "Zero-to-Hero courses, whatever. There is NO "non-approved" substitute for either the Practical element or the OJT.
Instead of the Practical Training and OJT, a student must complete an extra 3 years of work experience as a minimum, making 5 years in all. He or she then presents a completed logbook with all this experience duly logged and signed up, together with the Module exam certificates, which must be completed within the previous 5 years (I think).
The upshot is that one choice is to carry out a Fully approved course including Practical and OJT, with a Basic Training Certificate as an outcome, followed by 2 years work experience. This will probably take 4 years in all, and cost £15,000 - £20,000 before any Government funding, plus living costs for 2 years.
The other choice is to take the Module exams (£50 or so per exam plus travel) and obtain 5 years work experience working unlicensed, but paid, in a Part 145 MRO. You study and take the exams when off-duty, at little or no cost. This can be accomplished in 5 years in all. The main difficulty is getting the job in the first place, and to do that you have to be realistic about your value to the MRO. Contracting is a possible route for those with at least some training and experience.
(There are some differences for people with Service experience etc.)
All this means that a 2-year College course that does not include the OJT is a total waste of time and money if the rules are enforced; not being an Approved course the student will have to complete 5 years work experience in any case, while the Practical element of the course, while it might have taught some useful basic handskills, counts for nothing so far as EASA is concerned. You can get the same training much less expensively; evening classes is one way.
However, that's not the whole story. It may be that with the consent of the CAA Colleges are being allowed to make some arrangement for OJT that allows them to issue a Basic Training Certificate, while not fulfilling EASA requirements. Such an arrangement might be that the student goes off and obtains OJT somewhere, as instructed, and the College signs a retroactive contract with the provider, so that the OJT appears to have been provided by the College as part of the course. But it will not have been, and the OJT will not have been planned, supervised and monitored by the Part 147 MTO as it should have been. The arrangement is an obvious sham, in fact, but the evidence suggests that it exists.
If when you question the College about the course and particularly the OJT it appears that such an arrangement is used, you should walk away. You are not getting a proper fully-approved Basic course. But if you decide to continue, you should contact the CAA and obtain a statement, in writing, that although the OJT is not an integral part of the course the CAA will accept it as such, and that they consider the course to satisfy all the requirements for a Full-Approved course.
When considering the full cost of the course, remember to add in all the costs of the OJT if they are not included in the course price. That would be the charges by the MRO, any additional charges by the College, 10 weeks accommodation, 10 weeks loss of income, travel etc etc. And that is in the very unlikely event that you can walk into OJT immediately you finish at the College.
Good luck!