I recently converted my UK CAA 'National' licence to an EASA licence and found the whole thing really quite straight forward and the CAA very amiable, realistic and helpful
Among the type ratings on my 'National' licence I had my current type but I had not flown it on the UK licence for quite some time (about 15 years).
If converting from JAR to EASA it really is a matter of having a current type rating signed by an EASA TRE, an EASA Class 1 medical and, as alluded to above, language proficiency > 4. Converting from a 'National' licence wasn't that much more involved, only requiring another form to be filled in and a bit more money for a new licence. The JAR licence is swapped one-for-one with an EASA one and doesn't need to be paid for.
Dan's post is excellent and covers everything. The only thing I might say is that No.3 might only require you to pass an LPC, rather than an LST, depending on how long ago your EASA type rating lapsed. There seems to be an unwritten (???) 'rule' that > 3 years requires an LST but I couldn't find anything in the book and, since it's only the addition of a raw data approach anyway, I really could't be arsed to argue and just did an LST.
Might I suggest you contact BA Flight Training if you are considering this. They really were very good and did exactly what I needed to do without any money-making extras added on. I contacted another well known training provider who insisted that in order for them to sign my course completion certificate they required me to undergo 8 hours of 'training' before I could sit the LST. Remember that I am flying the type that was already on my UK licence and I am not flying for some tin pot operator in darkest Africa. These people were simply taking the piss and making up unrealistic numbers to bolster their coffers. BA saw that I was current on type and did the LST straight away. The TRE signed my English proficiency application there and then and I'm glad to say I was allowed a 6
I'd already done an EASA class 1 medical and nipped off to the Belgrano the next morning. About 1.5 hours later I left with an EASA ATPL, my current type as my current type rating in the front of the licence and all my old type ratings listed in the 'expired' list.
I spoke to the bloke dealing with my licence at the time and enquired about getting a new type put on my EASA licence once we start flying them and he confirmed what is written above i.e. EASA Class 1 medical, >500 hours, EASA LST and an application form/fee.
And finally, as Dan said, he confirmed there is no requirement to keep the type rating current unless you're going to need it for a job application etc and even then it seems pretty daft to do an LPC every year 'just in case'. If you need your licence to be 'current' then simply do an EASA Class 1 medical and an LPC/LST (depending on how long ago your type rating expired) and you're good to go.
Far from the doom an gloom purported by McNugget I found the whole process very straightforward and, using BA, relatively inexpensive..........although that would not have been so much the case with a certain training provider whose name entails rearranging 3 of the first 5 letters of the alphabet
