IR is 5 or 10 hours sim and 5 hours in an aircraft, again big savings if you come straight back to Europe and do it right away
If you have an overseas licence, particularly US, do not be fooled by the above. What is quoted is the absolute JAA minima. Ten hours sim is perhaps do-able, but 5 hours a/c including your 170a is very unrealistic. A lot of schools in the UK prepare you for test by flying diverse routes in the a/c - often potential routes where the CAA may take you. A typical route can be 1.7-2.0hrs flight time, so you do the maths. If you haven't seen an NDB before, I would add at least another 10 hours flight time onto that, if not more (so 15-20 hours on average)
CPL conversion is "as required" and is much more reasonable - if you have decent handling skills then all that is really needed is some navigation exercises, so 5-7 hours should be fine.