DETAILED UPDATE FOR THE BENEFIT OF OTHER MEMBERS:
I am in the UK now and I finally managed to send the money this morning through my bank's app as there are recent reports of great delays with Deemoney and the difference in fees would be less than 30 GBP.
Last month I went to my branch and asked how to doa tranfer while being abroad, and they told me I could use only the Buluang ibanking website and not the app. I thought to confirm this with the Bangkok Bank customer service while I was still in my branch, which was extremely helpful and knowledgable and they said my branch was wrong. Then customer service checked my account and found that my daily transfer limit was only 200,000 and had to be changed, this again was not detected or mentioned by the officer at my branch although I mentioned the amount I wanted to transfer. This change of the daily transfer limit could be done only by physically going to my branch and if I had not called customer service I would not be able to transfer the full amount from the UK. Then in the process of changing the limit the bank officer discovered that on the system they had my old passport details, although I changed my passport 4 years ago and shown my passport to my branch on multiple occasions over that period, without anyone bothering to update my details. On updating my passport details, they copied my passport and took a digital picture of my face. After that I had to designate the UK account that I wanted to receive the transfer funds in. Today I had to wake up at 02:30 a.m. UK time because the transaction could be done only on weekdays between 08:30-17:00 thai time. I logged in to Buluang ibanking and tried to do the transfer but I realized that the IBAN I designated in Thailand was partly incorrect and I was not able to change it although there was an option for changes. Then I tried to designate a new international transfer 3rd party account with the correct IBAN, I had to confirm this with an OTP number sent to my thai phone but I got the message that I had to wait for 3 business days for the new 3rd party account to take effect. Frustrated, as I needed to do the transfer today, I called customer service again on +66-26455555, which was again very helpful and advised to use the app instead of the web banking. With the app I managed to designate my UK account on the spot, but for verification the app asked to scan my face which was successfully confirmed. If I had not gone to my branch last month and my picture was taken, I very much doubt that I would be able to complete this step. Then following instructions I completed the whole transfer through SWIFT and I was told the funds would reach my UK account within 3 business days. Cost of the transfer : the THB on my account had to be exchanged to GBP using BBK Bank's own foreign exchange rate ( the BILL-DD-TT SELLING RATE) which is found here: https://www.bangkokbank.com/en/Personal/Other-Services/View-Rates/Foreign-Exchange-Rates and is a little higher than the official rate found on the internet. I chose to pay for both banks' fees which was a flat rate of 1,050 baht.
For int'l transfers using the app you need to click on : "more services" at the low right corner, then scroll down to "International transfers" and select "SWIFT". Remember it can be done only on weekdays between 08:30-17:00 thai time.
Thanks for all your replies, hope the above is helpful.